arm64: acpi: Enable ACPI CCEL support

Add support for ACPI CCEL by handling the EfiACPIMemoryNVS type memory.
As per UEFI specifications NVS memory is reserved for Firmware use even
after exiting boot services. Thus map the region as read-only.

Cc: Sami Mujawar <sami.mujawar@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Gavin Shan <gshan@redhat.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Tested-by: Sami Mujawar <sami.mujawar@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>