nfs/blocklayout: Use the passed in gfp flags

[ Upstream commit 08b45fcb2d4675f6182fe0edc0d8b1fe604051fa ]

This allocation should use the passed in GFP_ flags instead of
GFP_KERNEL.  One places where this matters is in filelayout_pg_init_write()
which uses GFP_NOFS as the allocation flags.

Fixes: 5c83746a ("pnfs/blocklayout: in-kernel GETDEVICEINFO XDR parsing")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>