qemu_firmware: Report NVRAM template path for ROMs

This was not necessary until now since ROMs couldn't have an
associate NVRAM template, and technically speaking they still
can't; however, the varstore template serves essentialy the
same purpose.

The qemuFirmwareGetSupported() helper is used in two places:
one is the code that is responsible for filling in domaincaps,
where templates are ignored so this change has no impact on it;
the other is the qemufirmware test program, where this value
being reported is useful as it will allow us to confirm that
the JSON firmware descriptors for uefi-vars enabled builds are
parsed correctly.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

src/qemu/qemu_firmware.c

@@ -2161,6 +2161,7 @@ qemuFirmwareGetSupported(const char *machine,
 
         case QEMU_FIRMWARE_DEVICE_MEMORY:
             fwpath = memory->filename;
+            nvrampath = memory->template;
             break;
 
         case QEMU_FIRMWARE_DEVICE_NONE: