Fix random config build warnings:

Implicit-function-declaration ‘__raw_writel’
Cast to pointer from integer of different size [-Wint-to-pointer-cast]
Reviewed-by: NBruce Allan <bruce.w.allan@intel.com>
Signed-off-by: NTadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>