mtip32xx: kill atomic argument to mtip_quiesce_io()

All callers now pass in GFP_KERNEL, get rid of the argument.

Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>