AVR: Outsource lib1func.S's macros to asm-defs.h.

libgcc/
	* config/avr/lib1funcs.S: Fix trailing blanks.
	(mov_h): Remove macro and invocations.
	(mov_l): Remove macro.  Replace invocations with wmov.
	(__zero_reg__, __tmp_reg__, __SREG__, __SP_H__)
	(__SP_L__, __RAMPZ__, __EIND__, skip, NEG2, NEG4)
	(wmov, wsubi, waddi, mov4, XCALL, XJMP, XICALL, XIJMP)
	(do_prologue_saves, do_epilogue_restores, .branch_plus)
	(DEFUN, ENDF, FALIAS): Move macros to...
	* config/avr/asm-defs.h: ...this new file.
	* config/avr/lib1funcs-fixed.S: Fix trailing blanks.