[PATCH] powerpc: Expose SMT and L1 icache snoop userland features

This patch makes userland aware of the icache snoop capability of the
POWER5 (and possibly others in the future) and of SMT capabilities.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>