MIPS: Lemote 2F: Add PCI support

PCI support for the Fuloong 2E and Lemote Loongson 2F family machines is
mostly identical with the exception of CS5536 support.

Rename ops-fuloong2e.c to ops-loongson2.c then add the CS5536 support to
share most of the source code among Loongson machines.

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: zhangfx@lemote.com
Cc: yanh@lemote.com 
Cc: huhb@lemote.com
Cc: Nicholas Mc Guire <hofrat@hofr.at>
Cc: Arnaud Patard <apatard@mandriva.com>
Cc: loongson-dev@googlegroups.com
Cc: linux-mips@linux-mips.org
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>