ubsan: epiphany: left shift of negative value

ubsan: epiphany: left shift of negative value

Two places in epiphany_cgen_extract_operand, "value" is a long.
        value = ((((value) << (1))) + (pc));

cpu/
	* epiphany.cpu (f-simm8, f-simm24): Use multiply rather than
	shift left to avoid UB on left shift of negative values.
opcodes/
	* epiphany-ibld.c: Regenerate.