sparc64: Add detection for features new in SPARC-T4.

Compare and branch, pause, and the various new cryptographic opcodes.

We advertise the crypto opcodes to userspace using one hwcap bit,
HWCAP_SPARC_CRYPTO.

This essentially indicates that the %cfr register can be interrograted
and used to determine exactly which crypto opcodes are available on
the current cpu.

We use the %cfr register to report all of the crypto opcodes available
in the bootup CPU caps log message, and via /proc/cpuinfo.

Signed-off-by: David S. Miller <davem@davemloft.net>