Upgrade rb532 to .23, provide generic GPIO API to this board

target/linux/rb532/Makefile

target/linux/rb532/config-2.6.23

target/linux/rb532/files/arch/mips/pci/fixup-rb500.c

target/linux/rb532/files/arch/mips/rb500/Makefile

target/linux/rb532/files/arch/mips/rb500/gpio.c

target/linux/rb532/files/arch/mips/rb500/irq.c

target/linux/rb532/files/arch/mips/rb500/misc.c

target/linux/rb532/files/arch/mips/rb500/serial.c

target/linux/rb532/files/include/asm-mips/rc32434/gpio.h

target/linux/rb532/files/include/asm-mips/rc32434/rc32434.h

target/linux/rb532/patches/100-rb5xx_support.patch

target/linux/rb532/patches/120-cf.patch

target/linux/rb532/patches/140-cmdline_hack.patch

target/linux/rb532/patches/240-via_rhine_performance.patch

target/linux/rb532/patches/510-rb500_led.patch