arm64: acpi: Enable ACPI CCEL support

ACPI CCEL memory area is reported as Non-Volatile storage area. Map it as
PAGE_KERNEL.

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>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>