MAINTAINERS: add crc_kunit.c back to CRC LIBRARY

Restore lib/tests/crc_kunit.c to CRC LIBRARY following the rename in
commit db6fe4d61ece ("lib: Move KUnit tests into tests/ subdirectory")
which made it no longer match the file pattern lib/crc*.

Reviewed-by: Kees Cook <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Eric Biggers <[e-mail]>

MAINTAINERS

···
 F:	arch/*/lib/crc*
 F:	include/linux/crc*
 F:	lib/crc*
+F:	lib/tests/crc_kunit.c
 F:	scripts/gen-crc-consts.py
 
 CREATIVE SB0540