f2fs: remove F2FS_SET_FEATURE() and F2FS_CLEAR_FEATURE() macro

F2FS_SET_FEATURE() and F2FS_CLEAR_FEATURE() have never
been used since they were introduced by this commit
76f105a2

("f2fs: add feature facility in superblock").

So let's remove them. BTW, convert f2fs_sb_has_##name to return bool.

Signed-off-by: Yangtao Li <frank.li@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>