MAINTAINERS: update ARM SMMU entry

Ensure that the short-descriptor page table code is included under the
SMMU entry, and add Robin as a designated reviewer.
Acked-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

MAINTAINERS

@@ -1793,11 +1793,13 @@ F:	drivers/edac/synopsys_edac.c
 
 ARM SMMU DRIVERS
 M:	Will Deacon <will.deacon@arm.com>
+R:	Robin Murphy <robin.murphy@arm.com>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 S:	Maintained
 F:	drivers/iommu/arm-smmu.c
 F:	drivers/iommu/arm-smmu-v3.c
 F:	drivers/iommu/io-pgtable-arm.c
+F:	drivers/iommu/io-pgtable-arm-v7s.c
 
 ARM64 PORT (AARCH64 ARCHITECTURE)
 M:	Catalin Marinas <catalin.marinas@arm.com>