quota: Drop GFP_NOFS instances under dquot->dq_lock and dqio_sem

Quota code acquires dquot->dq_lock whenever reading / writing dquot.
When reading / writing quota info we hold dqio_sem.  Since these locks
can be acquired during inode reclaim (through dquot_drop() -> dqput() ->
dquot_release()) we are setting nofs allocation context whenever
acquiring these locks. Hence there's no need to use GFP_NOFS allocations
in quota code doing IO. Just switch it to GFP_KERNEL.

Signed-off-by: Jan Kara <jack@suse.cz>