quota: Make VFS quotas use new interface for getting quota info

Create new internal interface for getting information about quota which
contains everything needed for both VFS quotas and XFS quotas. Make VFS
use this and hook it up to Q_GETINFO.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
index df73258..6509a29 100644
--- a/include/linux/quotaops.h
+++ b/include/linux/quotaops.h
@@ -95,7 +95,7 @@
 int dquot_quota_off(struct super_block *sb, int type);
 int dquot_writeback_dquots(struct super_block *sb, int type);
 int dquot_quota_sync(struct super_block *sb, int type);
-int dquot_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii);
+int dquot_get_state(struct super_block *sb, struct qc_state *state);
 int dquot_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii);
 int dquot_get_dqblk(struct super_block *sb, struct kqid id,
 		struct qc_dqblk *di);