[PATCH] powerpc: Move pSeries firmware feature setup into platforms/pseries

Currently we have some stuff in firmware.h and kernel/firmware.c that is
#ifdef CONFIG_PPC_PSERIES. Move it all into platforms/pseries.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>