x86: quark: Use Quark's own PCI config APIs

There are still two places in Quark's MRC codes that use the generic
legacy PCI APIs, but as we are phasing out these legacy APIs, switch
to use Quark's own PCI config routines.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>