[GFS2] Remove unused prototype

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

fs/gfs2/bmap.h

@@ -22,7 +22,6 @@ int gfs2_block_map(struct gfs2_inode *ip,
 		   uint64_t lblock, int *new,
 		   uint64_t *dblock, uint32_t *extlen);
 
-typedef int (*gfs2_truncator_t) (struct gfs2_inode * ip, uint64_t size);
 int gfs2_truncatei(struct gfs2_inode *ip, uint64_t size);
 int gfs2_truncatei_resume(struct gfs2_inode *ip);
 int gfs2_file_dealloc(struct gfs2_inode *ip);