[efi] Remove the Dhcp6Dxe driver veto

Commit cb95b5b ("[efi] Veto the Dhcp6Dxe driver on all platforms")
vetoed the Dhcp6Dxe driver to work around the bug described at
https://github.com/tianocore/edk2/issues/10506 that results in
EfiDhcp6Stop() getting stuck in a tight loop waiting for an event that
will never occur.

Since we now call UnloadImage() at TPL_APPLICATION, we no longer
trigger the bug in Dhcp6Dxe, and so the veto may be removed.

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

src/interface/efi/efi_veto.c

@@ -480,30 +480,6 @@ efi_veto_vmware_uefipxebc ( EFI_DRIVER_BINDING_PROTOCOL *binding __unused,
 	return 1;
 }
 
-/**
- * Veto Dhcp6Dxe driver
- *
- * @v binding		Driver binding protocol
- * @v loaded		Loaded image protocol
- * @v manufacturer	Manufacturer name, if present
- * @v name		Driver name, if present
- * @ret vetoed		Driver is to be vetoed
- */
-static int efi_veto_dhcp6 ( EFI_DRIVER_BINDING_PROTOCOL *binding __unused,
-			    EFI_LOADED_IMAGE_PROTOCOL *loaded __unused,
-			    const char *manufacturer __unused,
-			    const CHAR16 *name ) {
-	static const CHAR16 dhcp6[] = L"DHCP6 Protocol Driver";
-
-	/* Check driver name */
-	if ( ! name )
-		return 0;
-	if ( memcmp ( name, dhcp6, sizeof ( dhcp6 ) ) != 0 )
-		return 0;
-
-	return 1;
-}
-
 /** Driver vetoes */
 static struct efi_veto_candidate efi_vetoes[] = {
 	{
@@ -518,10 +494,6 @@ static struct efi_veto_candidate efi_vetoes[] = {
 		.name = "VMware UefiPxeBc",
 		.veto = efi_veto_vmware_uefipxebc,
 	},
-	{
-		.name = "Dhcp6",
-		.veto = efi_veto_dhcp6,
-	},
 };
 
 /**