powerpc/pseries: Fix HV facility unavailable to use correct handler

The 0xf80 hv_facility_unavailable trampoline branches to the 0xf60
handler. This works because they both do the same thing, but it should
be fixed.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>