[GFS2] Fix Kconfig wrt CRC32

GFS2 requires the CRC32 library function. This was reported by
Toralf Förster.

Cc: Toralf Förster <toralf.foerster@gmx.de>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/Kconfig

@@ -2,6 +2,7 @@ config GFS2_FS
 	tristate "GFS2 file system support"
 	depends on EXPERIMENTAL
 	select FS_POSIX_ACL
+	select CRC32
 	help
 	A cluster filesystem.