of: of_test: add MODULE_DESCRIPTION()

Fix the 'make W=1' warning:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/of/of_test.o

Signed-off-by: Jeff Johnson <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Rob Herring (Arm) <[e-mail]>

drivers/of/of_test.c

···
 kunit_test_suites(
 	&of_dtb_suite,
 );
+MODULE_DESCRIPTION("KUnit tests for OF APIs");
 MODULE_LICENSE("GPL");