ARC: add asm-compat macros

Add asm-compat macroses to be able to co create assembler code
which works and can be build for both ARCv2 and ARCv3 ISAs

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Evgeniy Paltsev <PaltsevEvgeniy@gmail.com>