f2fs: clean up redundant function call

This patch integrates inode_[inc|dec]_dirty_dents with inc_page_count to remove
redundant calls.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index aeff132..4841d12 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -662,6 +662,7 @@
 
 static inline void inode_inc_dirty_dents(struct inode *inode)
 {
+	inc_page_count(F2FS_SB(inode->i_sb), F2FS_DIRTY_DENTS);
 	atomic_inc(&F2FS_I(inode)->dirty_dents);
 }
 
@@ -672,6 +673,10 @@
 
 static inline void inode_dec_dirty_dents(struct inode *inode)
 {
+	if (!S_ISDIR(inode->i_mode))
+		return;
+
+	dec_page_count(F2FS_SB(inode->i_sb), F2FS_DIRTY_DENTS);
 	atomic_dec(&F2FS_I(inode)->dirty_dents);
 }