Implement {spe,sve}_supported() helpers and refactor code

Implement helpers to test if the core supports SPE/SVE.  We have a
similar helper for AMU and this patch makes all extensions consistent
in their implementation.

Change-Id: I3e6f7522535ca358259ad142550b19fcb883ca67
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
4 files changed