powerpc: Setup in HFSCR for POWER8

Setup the HFSCR (Hypervisor Facility Status and Control Register) for POWER8
when running HV=1.  The HFSCR is the same as the FSCR except it's for
hypervisors.  It controls the available of various facilities in OS and
userspace levels.  It also indicates the cause of a hypervisor facility
unavailable interrupt (although we are not using this here).

This patch sets the facilities Linux knows about incase the firmware doesn't.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>