arm64: Change type of hsr, cpsr, spsr_el1 to uint64_t

arm64: Change type of hsr, cpsr, spsr_el1 to uint64_t

AArch64 registers are 64bit whereas AArch32 registers
are 32bit or 64bit. MSR/MRS are expecting 64bit values thus
we should get rid of helpers READ/WRITE_SYSREG32
in favour of using READ/WRITE_SYSREG.
We should also use register_t type when reading sysregs
which can correspond to uint64_t or uint32_t.
Even though many AArch64 registers have upper 32bit reserved
it does not mean that they can't be widen in the future.

Modify type of hsr, cpsr, spsr_el1 to uint64_t.
Previously we relied on the padding after spsr_el1.
As we removed the padding, modify the union to be 64bit so we don't corrupt spsr_fiq.
No need to modify the assembly code because the accesses were based on 64bit
registers as there was a 32bit padding after spsr_el1.

Remove 32bit padding in cpu_user_regs before spsr_fiq
as it is no longer needed due to upper union being 64bit now.
Add 64bit padding in cpu_user_regs before spsr_el1
because the kernel frame should be 16-byte aligned.

Change type of cpsr to uint64_t in the public outside interface
"public/arch-arm.h" to allow ABI compatibility between 32bit and 64bit.
Increment XEN_DOMCTL_INTERFACE_VERSION.

Change type of cpsr to uint64_t in the public outside interface
"public/vm_event.h" to allow ABI compatibility between 32bit and 64bit.

Signed-off-by: Michal Orzel <michal.orzel@arm.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>