[pxe] Fix interoperability with the Intel DOS UNDI driver

The Intel DOS UNDI driver fails when run on top of gPXE because we do
not fill in the ServiceFlags field in PXENV_UNDI_GET_IFACE_INFO.

Fix by filling in the ServiceFlags field with reasonable values
indicating our approximate feature capabilities.

src/arch/i386/include/pxe_api.h

 /** PXE API function code for pxenv_undi_get_iface_info() */
 #define	PXENV_UNDI_GET_IFACE_INFO	0x0013
 
+/** Broadcast supported */
+#define SUPPORTED_BROADCAST		0x0001
+/** Multicast supported */
+#define SUPPORTED_MULTICAST		0x0002
+/** Functional/group addressing supported */
+#define SUPPORTED_GROUP			0x0004
+/** Promiscuous mode supported */
+#define SUPPORTED_PROMISCUOUS		0x0008
+/** Software settable station address */
+#define SUPPORTED_SET_STATION_ADDRESS	0x0010
+/** InitiateDiagnostics supported */
+#define SUPPORTED_DIAGNOSTICS		0x0040
+/** Reset MAC supported */
+#define SUPPORTED_RESET			0x0400
+/** Open / Close Adapter supported */
+#define SUPPORTED_OPEN_CLOSE		0x0800
+/** Interrupt Request supported */
+#define SUPPORTED_IRQ			0x1000
+
 /** Parameter block for pxenv_undi_get_iface_info() */
 struct s_PXENV_UNDI_GET_IFACE_INFO {
 	PXENV_STATUS_t	Status;		/**< PXE status code */

src/arch/i386/interface/pxe/pxe_undi.c

 	snprintf ( ( char * ) undi_get_iface_info->IfaceType,
 		   sizeof ( undi_get_iface_info->IfaceType ), "gPXE" );
 	undi_get_iface_info->LinkSpeed = 10000000; /* 10 Mbps */
-	undi_get_iface_info->ServiceFlags = 0;
+	undi_get_iface_info->ServiceFlags =
+		( SUPPORTED_BROADCAST | SUPPORTED_MULTICAST |
+		  SUPPORTED_SET_STATION_ADDRESS | SUPPORTED_RESET |
+		  SUPPORTED_OPEN_CLOSE | SUPPORTED_IRQ );
 	memset ( undi_get_iface_info->Reserved, 0,
 		 sizeof(undi_get_iface_info->Reserved) );