* config/avr/avr.h (mcu_type_s): Add errata_skip field.
	* config/avr/avr-devices.c (avr_mcu_types): Use it.
	* config/avr/avr-mcus.def (AVR_MCU): Use it.
	* config/avr/avr-c.c (avr_cpu_cpp_builtins): Use it to builtin
	define __AVR_ERRATA_SKIP__ and __AVR_ERRATA_SKIP_JMP_CALL__.
	* config/avr/libgcc.S (__mulshisi3, __ffshi2, __fmulsu_exit):
	Use __AVR_ERRATA_SKIP_JMP_CALL__ instead of __AVR_HAVE_JMP_CALL__
	to detect if XJMP must not be skipped.

From-SVN: r177049