MAINTAINERS: Cover Arm SMMU DT bindings

We'd like to be aware of proposed DT binding changes even when they
don't directly touch the drivers themselves.

Signed-off-by: Robin Murphy <[email protected]>
Signed-off-by: Will Deacon <[email protected]>

Author: rmurphy-arm

MAINTAINERS

@@ -1426,6 +1426,7 @@ M:	Will Deacon <[email protected]>
 R:	Robin Murphy <[email protected]>
 L:	[email protected] (moderated for non-subscribers)
 S:	Maintained
+F:	Documentation/devicetree/bindings/iommu/arm,smmu*
 F:	drivers/iommu/arm-smmu*
 F:	drivers/iommu/io-pgtable-arm.c
 F:	drivers/iommu/io-pgtable-arm-v7s.c