xfs: don't use __GFP_RETRY_MAYFAIL in xfs_initialize_perag

__GFP_RETRY_MAYFAIL increases the likelyhood of allocations to fail,
which isn't really helpful during log recovery.  Remove the flag and
stick to the default GFP_KERNEL policies.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>