* config/tc-avr.c: Add specified_mcu variable for selected mcu.
	(enum options): add OPTION_RMW_ISA for -mrmw option.
	(struct option md_longopts): Add mrmw option.
	(md_show_usage): add -mrmw option description.
	(md_parse_option): Update isa details if -mrmw option specified.
	* doc/c-avr.texi: Add doc for new option -mrmw.
	* gas/avr/avr.exp: Run new tests.
	* gas/avr/rmw.d: Add test for additional ISA support.
	* gas/avr/rmw.s: Ditto.
	* gas/ChangeLog: Revert
	* gas/config/tc-avr.c: Revert
	* gas/doc/c-avr.texi: Revert
	* gas/testsuite/ChangeLog: Revert
	* gas/testsuite/gas/avr/avr.exp: Revert
	* gas/testsuite/gas/avr/rmw.d: Revert
	* gas/testsuite/gas/avr/rmw.s: Revert

	This reverts commit d24e46e3e247e46eb2f5e7ebb5efd0f9fcc5fcdd.
	* config/tc-avr.c: Add specified_mcu variable for selected mcu.
	(enum options): add OPTION_RMW_ISA for -mrmw option.
	(struct option md_longopts): Add mrmw option.
	(md_show_usage): add -mrmw option description.
	(md_parse_option): Update isa details if -mrmw option specified.
	* doc/c-avr.texi: Add doc for new option -mrmw.
	* gas/avr/avr.exp: Run new tests.
	* gas/avr/rmw.d: Add test for additional ISA support.
	* gas/avr/rmw.s: Ditto.