[GFS2] Remove unused entry in ioctl-number.txt

GFS2 doesn't use any ioctl numbers of its own, so we
don't need a reserved range of numbers for it.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

Documentation/ioctl-number.txt

@@ -124,7 +124,6 @@ Code	Seq#	Include File		Comments
 'e'	00-1F	linux/video_encoder.h	conflict!
 'e'	00-1F	net/irda/irtty.h	conflict!
 'f'	00-1F	linux/ext2_fs.h
-'g'	00-1F	linux/gfs2_ioctl.h
 'h'	00-7F				Charon filesystem
 					<mailto:zapman@interlan.net>
 'i'	00-3F	linux/i2o.h