powerpc/lib/feature-fixups: use raw_patch_instruction()

commit 8183d99f4a22c2abbc543847a588df3666ef0c0c upstream.

feature fixups need to use patch_instruction() early in the boot,
even before the code is relocated to its final address, requiring
patch_instruction() to use PTRRELOC() in order to address data.

But feature fixups applies on code before it is set to read only,
even for modules. Therefore, feature fixups can use
raw_patch_instruction() instead.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reported-by: David Gounaris <david.gounaris@infinera.com>
Tested-by: David Gounaris <david.gounaris@infinera.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>