ARC: clean out UAPI byteorder.h clean off Kconfig symbol

UAPI header should not use Kconfig items

Use __BIG_ENDIAN__ defined as a compiler intrinsic

Signed-off-by: Noam Camus <noamc@ezchip.com>
[vgupta: fix changelog]
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>