[golan] Fix building with GCC 6

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/drivers/infiniband/golan.c

 static void golan_destory_eq(struct golan *golan)
 {
 	struct golan_cmd_layout	*cmd;
+	struct golan_destroy_eq_mbox_in *in;
 	uint8_t eqn = golan->eq.eqn;
 	int rc;
 
 					sizeof(struct golan_destroy_eq_mbox_in),
 					sizeof(struct golan_destroy_eq_mbox_out));
 
-	((struct golan_destroy_eq_mbox_in *)(cmd->in))->eqn = eqn;
+	in = GOLAN_MBOX_IN ( cmd, in );
+	in->eqn = eqn;
 	rc = send_command_and_wait(golan, DEF_CMD_IDX, NO_MBOX, NO_MBOX, __FUNCTION__);
 	GOLAN_PRINT_RC_AND_CMD_STATUS;
 
 static int golan_query_vport_context ( struct ib_device *ibdev ) {
 	struct golan *golan = ib_get_drvdata ( ibdev );
 	struct golan_cmd_layout	*cmd;
+	struct golan_query_hca_vport_context_inbox *in;
 	struct golan_query_hca_vport_context_data *context_data;
 	int rc;
 
 			sizeof(struct golan_query_hca_vport_context_inbox),
 			sizeof(struct golan_query_hca_vport_context_outbox) );
 
-	((struct golan_query_hca_vport_context_inbox *)(cmd->in))->port_num = (u8)ibdev->port;
+	in = GOLAN_MBOX_IN ( cmd, in );
+	in->port_num = (u8)ibdev->port;
 
 	rc = send_command_and_wait ( golan, DEF_CMD_IDX, GEN_MBOX, GEN_MBOX, __FUNCTION__ );
 	GOLAN_CHECK_RC_AND_CMD_STATUS( err_query_vport_context_cmd );
 static int golan_query_vport_gid ( struct ib_device *ibdev ) {
 	struct golan *golan = ib_get_drvdata( ibdev );
 	struct golan_cmd_layout	*cmd;
+	struct golan_query_hca_vport_gid_inbox *in;
 	union ib_gid *ib_gid;
 	int rc;
 
 			sizeof(struct golan_query_hca_vport_gid_inbox),
 			sizeof(struct golan_query_hca_vport_gid_outbox) );
 
-	((struct golan_query_hca_vport_gid_inbox *)(cmd->in))->port_num = (u8)ibdev->port;
-	((struct golan_query_hca_vport_gid_inbox *)(cmd->in))->gid_index = 0;
+	in = GOLAN_MBOX_IN ( cmd, in );
+	in->port_num = (u8)ibdev->port;
+	in->gid_index = 0;
 	rc = send_command_and_wait ( golan, DEF_CMD_IDX, GEN_MBOX, GEN_MBOX, __FUNCTION__ );
 	GOLAN_CHECK_RC_AND_CMD_STATUS( err_query_vport_gid_cmd );
 
 static int golan_query_vport_pkey ( struct ib_device *ibdev ) {
 	struct golan *golan = ib_get_drvdata ( ibdev );
 	struct golan_cmd_layout	*cmd;
+	struct golan_query_hca_vport_pkey_inbox *in;
 	//struct golan_query_hca_vport_pkey_data *pkey_table;
 	int pkey_table_size_in_entries = (1 << (7 + golan->caps.pkey_table_size));
 	int rc;
 			sizeof(struct golan_outbox_hdr) + 8 +
 			sizeof(struct golan_query_hca_vport_pkey_data) * pkey_table_size_in_entries );
 
-	((struct golan_query_hca_vport_pkey_inbox *)(cmd->in))->port_num = (u8)ibdev->port;
-	((struct golan_query_hca_vport_pkey_inbox *)(cmd->in))->pkey_index = 0xffff;
+	in = GOLAN_MBOX_IN ( cmd, in );
+	in->port_num = (u8)ibdev->port;
+	in->pkey_index = 0xffff;
 	rc = send_command_and_wait ( golan, DEF_CMD_IDX, GEN_MBOX, GEN_MBOX, __FUNCTION__ );
 	GOLAN_CHECK_RC_AND_CMD_STATUS( err_query_vport_pkey_cmd );
 

src/drivers/infiniband/golan.h

 #define GET_INBOX(golan, idx)		(&(((struct mbox *)(golan->mboxes.inbox))[idx]))
 #define GET_OUTBOX(golan, idx)		(&(((struct mbox *)(golan->mboxes.outbox))[idx]))
 
+#define GOLAN_MBOX_IN( cmd_ptr, in_ptr ) ( {				  \
+	union {								  \
+		__be32 raw[4];						  \
+		typeof ( *(in_ptr) ) cooked;				  \
+	} *u = container_of ( &(cmd_ptr)->in[0], typeof ( *u ), raw[0] ); \
+	&u->cooked; } )
+
 #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
 
 /* Fw status fields */