The Arm and Aarch64 source files for ArmGicArchLib are copy/paste of each other with one minor difference to how they check for if the platform has GICv3.
I made the change in two patches so that the diff could be identified separately from the move commit.
The first patch makes both the Arm and Aarch64 versions identical and uses conditional compilation to handle Arm vs Aarch64.
[PATCH v2 1/2] ArmPkg/ArmGicLibArchLib: common check for GICv3
The second patch then removes the duplication in favour of a single source file.
[PATCH v2 2/2] ArmPkg/ArmGicArchLib: use common source file
Changes since v1 - rename new function from ArmGicArchLibHasGicv3 to GicSystemRegistersSupported - make new function STATIC - remove whitespace change - keep the version with the space before and after '|'