[PATCH] ifdef ->quota_read, ->quota_write

All suppliers of ->quota_read, ->quota_write (I've found ext2, ext3, UFS,
reiserfs) already have them properly ifdeffed.  All callers of
->quota_read, ->quota_write are under CONFIG_QUOTA umbrella, so...

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>