iommu: Properly pass gfp_t in _iommu_map() to avoid atomic sleeping

Sleeping while atomic = bad.  Let's fix an obvious typo to try to avoid it.

The warning that was seen (on a downstream kernel with the problematic
patch backported):

 BUG: sleeping function called from invalid context at mm/page_alloc.c:4726
 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 9, name: ksoftirqd/0
 CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.4.93-12508-gc10c93e28e39 #1
 Call trace:
  dump_backtrace+0x0/0x154
  show_stack+0x20/0x2c
  dump_stack+0xa0/0xfc
  ___might_sleep+0x11c/0x12c
  __might_sleep+0x50/0x84
  __alloc_pages_nodemask+0xf8/0x2bc
  __arm_lpae_alloc_pages+0x48/0x1b4
  __arm_lpae_map+0x124/0x274
  __arm_lpae_map+0x1cc/0x274
  arm_lpae_map+0x140/0x170
  arm_smmu_map+0x78/0xbc
  __iommu_map+0xd4/0x210
  _iommu_map+0x4c/0x84
  iommu_map_atomic+0x44/0x58
  __iommu_dma_map+0x8c/0xc4
  iommu_dma_map_page+0xac/0xf0

Fixes: d8c1df02

 ("iommu: Move iotlb_sync_map out from __iommu_map")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Yong Wu <yong.wu@mediatek.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210201170611.1.I64a7b62579287d668d7c89e105dcedf45d641063@changeid
Signed-off-by: Joerg Roedel <jroedel@suse.de>