iommu/virtio: Fix sparse warning

iommu/virtio: Fix sparse warning

We copied the virtio_iommu_config from the virtio-iommu specification,
which declares the fields using little-endian annotations (for example
le32). Unfortunately this causes sparse to warn about comparison between
little- and cpu-endian, because of the typecheck() in virtio_cread():

drivers/iommu/virtio-iommu.c:1024:9: sparse: sparse: incompatible types in comparison expression (different base types):
drivers/iommu/virtio-iommu.c:1024:9: sparse:    restricted __le64 *
drivers/iommu/virtio-iommu.c:1024:9: sparse:    unsigned long long *
drivers/iommu/virtio-iommu.c:1036:9: sparse: sparse: incompatible types in comparison expression (different base types):
drivers/iommu/virtio-iommu.c:1036:9: sparse:    restricted __le64 *
drivers/iommu/virtio-iommu.c:1036:9: sparse:    unsigned long long *
drivers/iommu/virtio-iommu.c:1040:9: sparse: sparse: incompatible types in comparison expression (different base types):
drivers/iommu/virtio-iommu.c:1040:9: sparse:    restricted __le64 *
drivers/iommu/virtio-iommu.c:1040:9: sparse:    unsigned long long *
drivers/iommu/virtio-iommu.c:1044:9: sparse: sparse: incompatible types in comparison expression (different base types):
drivers/iommu/virtio-iommu.c:1044:9: sparse:    restricted __le32 *
drivers/iommu/virtio-iommu.c:1044:9: sparse:    unsigned int *
drivers/iommu/virtio-iommu.c:1048:9: sparse: sparse: incompatible types in comparison expression (different base types):
drivers/iommu/virtio-iommu.c:1048:9: sparse:    restricted __le32 *
drivers/iommu/virtio-iommu.c:1048:9: sparse:    unsigned int *
drivers/iommu/virtio-iommu.c:1052:9: sparse: sparse: incompatible types in comparison expression (different base types):
drivers/iommu/virtio-iommu.c:1052:9: sparse:    restricted __le32 *
drivers/iommu/virtio-iommu.c:1052:9: sparse:    unsigned int *

Although virtio_cread() does convert virtio-endian (in our case
little-endian) to cpu-endian, the typecheck() needs the two arguments to
have the same endianness. Do as UAPI headers of other virtio devices do,
and remove the endian annotation from the device config.

Even though we change the UAPI this shouldn't cause any regression since
QEMU, the existing implementation of virtio-iommu that uses this header,
already removes the annotations when importing headers.

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/r/20200326093558.2641019-2-jean-philippe@linaro.org
Signed-off-by: Joerg Roedel <jroedel@suse.de>