This patch makes sure that a caller of pmac_call_feature() won't try
to call into ppc_md.feature_call of another platform, which might
happen if some powermac drivers are loaded on non-powermac machines.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>