Support for ARMv8 AArch32 optional features

Queries and returns following features if supported
(x) AES - Support for AES instructions
(x) PMULL - Support for 64-bit PMULL/PMULL2 instructions
(x) CRC32 - Support for CRC32 instructions
(x) SHA2 - Support for SHA2 instructions
(x) SHA1 - Support for SHA1 instructions

The features are determined based on the call to
getauxval() in libc with AT_HWCAP2 as parameter.

Change-Id: I9d336c4dbd7b91ebda819d50b27aa92c69793f0a
Signed-off-by: Ashok Bhat <ashok.bhat@arm.com>
Merge "Support for ARMv8 AArch32 optional features"