[myri10ge] Fix compilation error in myri10ge_command() with gcc 4.7

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

src/drivers/net/myri10ge.c

 	command->response_addr.high = 0;
 	command->response_addr.low
 		= htonl ( virt_to_bus ( &priv->dma->command_response ) );
-	for ( i=0; i<36; i+=4 )
-		* ( uint32 * ) &command->pad[i] = 0;
+	for ( i=0; i<9; i++ )
+		command->pad[i] = 0;
 	wmb();
-	* ( uint32 * ) &command->pad[36] = 0;
+	command->pad[9] = 0;
 
 	/* Wait up to 2 seconds for a response. */
 

src/drivers/net/myri10ge_mcp.h

   /* 16 */
   struct mcp_dma_addr response_addr;
   /* 24 */
-  uint8_t pad[40];
+  uint32_t pad[10];
 };
 typedef struct mcp_cmd mcp_cmd_t;