avr32: Introduce arch/avr32/mach-*/include/mach

Add arch/avr32/mach-*/include to include search path and copy all the
files from include/asm/arch there. The old files will be removed once
ARM does the same change and all common drivers are converted.

Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>