Use devm_ioremap_resource instead of devm_request_and_ioremap.

This was partly done using the semantic patch
scripts/coccinelle/api/devm_ioremap_resource.cocci

The error-handling code on the call to platform_get_resource was removed
manually, and the initialization of smmu->size was manually moved lower, to
take advantage of the NULL test on res performed by devm_ioremap_resource.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Will Deacon <will.deacon@arm.com>