xen: arm: introduce arm32 as a subarch of arm.
- move 32-bit specific files into subarch specific arm32 subdirectory.
- move gic.h to xen/include/asm-arm (it is needed from both subarch
and generic code).
- make the appropriate build and config file changes to support
XEN_TARGET_ARCH=arm32.
This prepares us for an eventual 64-bit subarch.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>