Consolidate the entries for SHA512 and SHA256 since they are being released
together.
List the algorithms generically as SHA-2 since this also applies to SHA224
and SHA384.
Clearly state that the instructions are only supported when building for
Aarch64 (64-bit ARMv8+) and not for Aarch32 (32-bit ARMv8+).
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
