xen/arm: Sync sysregs and cpuinfo with Linux 5.18-rc3

xen/arm: Sync sysregs and cpuinfo with Linux 5.18-rc3

Sync existing ID registers sanitization with the status of Linux kernel
version 5.18-rc3 and add sanitization of ISAR2 registers.

Sync sysregs.h bit shift defintions with the status of Linux kernel
version 5.18-rc3.

Changes in this patch are splitted in a number of patches in Linux
kernel and, as the previous synchronisation point was not clear, the
changes are done in one patch with a status possible to compare easily
by diffing Xen files to Linux kernel files.

Origin: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git b2d229d4ddb1
Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>