Import Joyent/SmartOS fix for BIOS extended write.

This is taken from the bug report:
"OS-6604 uefi-edk2 needs to support extended write for bhyve"
https://smartos.org/bugview/OS-6604

 and the patch from
TritonDataCenter/illumos-extra@065d8bd

BhyvePkg/Csm/BhyveCsm16/Bios.c

@@ -197,6 +197,22 @@ InterruptVector0x13(EFI_IA32_REGISTER_SET *Regs)
 
     Status = mDeviceBlockIo->ReadBlocks(mDeviceBlockIo, mDeviceBlockIo->Media->MediaId, AddressPacket->Lba, AddressPacket->NumberOfBlocks * mDeviceBlockIo->Media->BlockSize, (VOID *)(UINT64)(((AddressPacket->SegOffset >> 16) << 4) + (UINT16)AddressPacket->SegOffset));
 
+    DPRINTF (DBG_VERB, ("XXX Status = 0x%x\n", Status));
+    Regs->E.EFlags.CF = 0;
+    Regs->H.AH = 0;
+    break;
+  case 0x43:    /* Extended Write */
+    DPRINTF (DBG_VERB, ("XXX InterruptVector0x13() Extended Write Drive=0%x Packet=0x%x:0x%x\n", Regs->H.DL, Regs->E.DS, Regs->X.SI));
+    AddressPacket = (EDD_DEVICE_ADDRESS_PACKET *)(UINT64)((Regs->X.DS << 4) + (Regs->X.SI));
+
+    DPRINTF (DBG_VERB, ("XXX Packet->NumberOfBlocks=%d\n", AddressPacket->NumberOfBlocks));
+    DPRINTF (DBG_VERB, ("XXX Packet->Lba=0x%llx\n", AddressPacket->Lba));
+    DPRINTF (DBG_VERB, ("XXX Packet->SegOffset=0x%x\n", AddressPacket->SegOffset));
+    DPRINTF (DBG_VERB, ("XXX Packet->TransferBuffer=0x%llx\n", AddressPacket->TransferBuffer));
+    DPRINTF (DBG_VERB, ("XXX Segment 0x%x Offset=0x%x %x\n", AddressPacket->SegOffset >> 16, AddressPacket->SegOffset & 0xffff, (((AddressPacket->SegOffset >> 16) << 4) + (UINT16)AddressPacket->SegOffset)));
+
+    Status = mDeviceBlockIo->WriteBlocks(mDeviceBlockIo, mDeviceBlockIo->Media->MediaId, AddressPacket->Lba, AddressPacket->NumberOfBlocks * mDeviceBlockIo->Media->BlockSize, (VOID *)(UINT64)(((AddressPacket->SegOffset >> 16) << 4) + (UINT16)AddressPacket->SegOffset));
+
     DPRINTF (DBG_VERB, ("XXX Status = 0x%x\n", Status));
     Regs->E.EFlags.CF = 0;
     Regs->H.AH = 0;