KVM: arm64: selftests: Introduce and use hardware-definition macros

KVM: arm64: selftests: Introduce and use hardware-definition macros

The kvm selftest library for arm64 currently configures the hardware
fields, such as shift and mask in the page-table entries and registers,
directly with numbers. While it add comments at places, it's better to
rewrite them with appropriate macros to improve the readability and
reduce the risk of errors. Hence, introduce macros to define the
hardware fields and use them in the arm64 processor library.

Most of the definitions are primary copied from the Linux's header,
arch/arm64/include/asm/pgtable-hwdef.h.

No functional change intended.

Suggested-by: Oliver Upton <oupton@google.com>
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Link: https://lore.kernel.org/r/20250405001042.1470552-2-rananta@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>