* config/tc-arm.c (my_get_expression): Add handling of immediate
        prefix, under control of third tristate argument.
	(GE_NO_PREFIX, GE_IMM_PREFIX, GE_OPT_PREFIX): New macros.
	(expression_or_fail): Pass down third argument.
	(immediate_required_here, decode_shift, data_op2)
	(cp_address_required_here, parse_thumb_address, parse_operands):
	Update to match.  No need to handle immediate prefix here.
	(reg_list, ldst_extend, ldst_extend_v4, ld_mode_required_here)
	(do_ldst, do_ldstv4): Update to match.
	(cp_address_offset): Merge into cp_address_required_here.