f2fs: fix typo

Fix typo and some grammatical errors.

The words "filesystem" and "readahead" are being used without the space treewide.

Signed-off-by: Park Ju Hyung <qkrwngud825@gmail.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 0dfeeba..31b630e 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -62,7 +62,7 @@
 }
 
 /*
- * __find_rev_next(_zero)_bit is copied from lib/find_next_bit.c becasue
+ * __find_rev_next(_zero)_bit is copied from lib/find_next_bit.c because
  * f2fs_set_bit makes MSB and LSB reversed in a byte.
  * Example:
  *                             LSB <--> MSB
@@ -808,7 +808,7 @@
 }
 
 /*
- * This function always allocates a used segment (from dirty seglist) by SSR
+ * This function always allocates a used segment(from dirty seglist) by SSR
  * manner, so it should recover the existing segment information of valid blocks
  */
 static void change_curseg(struct f2fs_sb_info *sbi, int type, bool reuse)