MIPS: BCM63XX: enable pcie for BCM6362

The PCIe controller is almost the same as the BCM6328 one, with only
the SERDES register being at a different location.

Signed-off-by: Jonas Gorski <jogo@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/5011/


Acked-by: John Crispin <blogic@openwrt.org>