lib/igt_device_scan: Add missing Check for return value in scan_drm_devices

Return value of udev_enumerate_add_match_property() was not being checked
in scan_drm_devices().

Signed-off-by: Ayaz A Siddiqui <ayaz.siddiqui@intel.com>
Signed-off-by: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>

lib/igt_device_scan.c

@@ -532,7 +532,7 @@ static void scan_drm_devices(void)
 	ret = udev_enumerate_add_match_subsystem(enumerate, "drm");
 	igt_assert(!ret);
 
-	udev_enumerate_add_match_property(enumerate, "DEVNAME", "/dev/dri/*");
+	ret = udev_enumerate_add_match_property(enumerate, "DEVNAME", "/dev/dri/*");
 	igt_assert(!ret);
 
 	ret = udev_enumerate_scan_devices(enumerate);