MIPS: SGI-IP27: clean up bridge access and header files

MIPS: SGI-IP27: clean up bridge access and header files

Introduced bridge_read/bridge_write/bridge_set/bridge_clr for accessing
bridge register and get rid of volatile declarations. Also removed
all typedefs from arch/mips/include/asm/pci/bridge.h and cleaned up
language in arch/mips/pci/ops-bridge.c

Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org