* config/avr/avr-arch.h (avr_mcu_t): Add dev_attribute field to have device
	specific ISA/ feature information. Remove short_sp and errata_skip ds.
	Add avr_device_specific_features enum to have device specific info.
	* config/avr/avr-c.c (avr_cpu_cpp_builtins): use dev_attribute to check
	errata_skip. Add __AVR_ISA_RMW__ builtin macro if RMW ISA available.
	* config/avr/avr-devices.c (avr_mcu_types): Update AVR_MCU macro for
	updated device specific info.
	* config/avr/avr-mcus.def: Merge device specific details to
	dev_attribute field.
	* config/avr/avr.c (avr_2word_insn_p): use dev_attribute field to check
	errata_skip.
	* config/avr/avr.h (AVR_HAVE_8BIT_SP): same for short sp info.
	* config/avr/driver-avr.c (avr_device_to_as): Pass -mrmw option to
	assembler if RMW isa supported by current device.
	* config/avr/genmultilib.awk: Update as device info structure changed.
	* doc/invoke.texi: Add info for __AVR_ISA_RMW__ builtin macro

	* gcc.target/avr/dev-specific-rmw.c: New test.

From-SVN: r209141