avr32: drop unused CLEAN_FILES

Left over from before we used arch/avr32/include
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>

arch/avr32/Makefile

@@ -43,8 +43,6 @@ core-y					+= arch/avr32/mm/
 drivers-$(CONFIG_OPROFILE)		+= arch/avr32/oprofile/
 libs-y					+= arch/avr32/lib/
 
-CLEAN_FILES += include/asm-avr32/.arch include/asm-avr32/arch
-
 BOOT_TARGETS := vmlinux.elf vmlinux.bin uImage uImage.srec
 
 .PHONY: $(BOOT_TARGETS) install