bfin.c (must_save_p): New function, mostly broken out of n_dregs_to_save and n_pregs_...

bfin.c (must_save_p): New function, mostly broken out of n_dregs_to_save and n_pregs_to_save.

	* config/bfin/bfin.c (must_save_p): New function, mostly broken out of
	n_dregs_to_save and n_pregs_to_save.
	(n_pregs_to_save, n_dregs_to_save): Use it.  New argument CONSECUTIVE;
	all callers changed.
	(expand_prologue_reg_save, expand_epilogue_reg_restore): Enhance to be
	able to save single D/P registers that aren't saved by the push/pop
	multiple insns.

From-SVN: r130292