arm64/mm: Add FEAT_LPA2 specific ID_AA64MMFR0.TGRAN[2]

PAGE_SIZE support is tested against possible minimum and maximum values for
its respective ID_AA64MMFR0.TGRAN field, depending on whether it is signed
or unsigned. But then FEAT_LPA2 implementation needs to be validated for 4K
and 16K page sizes via feature specific ID_AA64MMFR0.TGRAN values. Hence it
adds FEAT_LPA2 specific ID_AA64MMFR0.TGRAN[2] values per ARM ARM (0487G.A).

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231127111737.1897081-5-ryan.roberts@arm.com