linux/pipe_fs_i.h: fix kernel-doc warnings after @wait was split

Fix kernel-doc warnings in struct pipe_inode_info after @wait was
split into @rd_wait and @wr_wait.

  include/linux/pipe_fs_i.h:66: warning: Function parameter or member 'rd_wait' not described in 'pipe_inode_info'
  include/linux/pipe_fs_i.h:66: warning: Function parameter or member 'wr_wait' not described in 'pipe_inode_info'

Fixes: 0ddad21d ("pipe: use exclusive waits when reading or writing")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/pipe_fs_i.h

@@ -29,7 +29,8 @@ struct pipe_buffer {
 /**
  *	struct pipe_inode_info - a linux kernel pipe
  *	@mutex: mutex protecting the whole thing
- *	@wait: reader/writer wait point in case of empty/full pipe
+ *	@rd_wait: reader wait point in case of empty pipe
+ *	@wr_wait: writer wait point in case of full pipe
  *	@head: The point of buffer production
  *	@tail: The point of buffer consumption
  *	@max_usage: The maximum number of slots that may be used in the ring