GFS2: Remove unused macro

The buffer_in_io() macro has been unused for some time,
so remove it.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/meta_io.h

@@ -77,8 +77,6 @@ struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen);
 
 #define buffer_busy(bh) \
 ((bh)->b_state & ((1ul << BH_Dirty) | (1ul << BH_Lock) | (1ul << BH_Pinned)))
-#define buffer_in_io(bh) \
-((bh)->b_state & ((1ul << BH_Dirty) | (1ul << BH_Lock)))
 
 #endif /* __DIO_DOT_H__ */