iommu/shmobile: Enable the driver on all ARM platforms

iommu/shmobile: Enable the driver on all ARM platforms

Renesas ARM platforms are transitioning from single-platform to
multi-platform kernels using the new ARCH_SHMOBILE_MULTI. Make the
driver available on all ARM platforms to enable it on both ARCH_SHMOBILE
and ARCH_SHMOBILE_MULTI, and increase build testing coverage with
COMPILE_TEST.

Cc: Joerg Roedel <[email protected]>
Cc: [email protected]
Signed-off-by: Laurent Pinchart <[email protected]>
Acked-by: Simon Horman <[email protected]>
Signed-off-by: Joerg Roedel <[email protected]>