PXA: Rename CONFIG_PXA2[57]X to CONFIG_CPU_PXA2[57]X

arch/arm/cpu/pxa/cpu.c

arch/arm/cpu/pxa/start.S

arch/arm/cpu/pxa/timer.c

arch/arm/cpu/pxa/usb.c

arch/arm/include/asm/arch-pxa/pxa-regs.h

common/lcd.c

drivers/mmc/pxa_mmc.c

drivers/mmc/pxa_mmc_gen.c

drivers/net/lan91c96.h

drivers/net/smc91111.h

drivers/serial/serial_pxa.c

drivers/serial/usbtty.h

drivers/usb/gadget/Makefile

include/configs/balloon3.h

include/configs/colibri_pxa270.h

include/configs/lubbock.h

include/configs/palmld.h

include/configs/palmtc.h

include/configs/pxa255_idp.h

include/configs/trizepsiv.h