iommu/tegra: smmu: Fix unsleepable memory allocation

commit 8f53dc724a83a0082184fa27df80c25c7df47340 upstream.

allo_pdir() is called in smmu_iommu_domain_init() with spin_lock
held. memory allocations in it have to be atomic/unsleepable.

Signed-off-by: Hiroshi DOYU <hdoyu@nvidia.com>
Reported-by: Chris Wright <chrisw@sous-sol.org>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>