RA: Use caller save equivalent memory only for LRA

RA: Use caller save equivalent memory only for LRA

Recently I submitted a patch to reuse memory with constant address for
caller saves optimization for constant or pure function call.  It
seems to work only for targets using LRA instead of the old reload
pass.  So the patch switches off this optimization when the old reload
pass is used.

        PR middle-end/108754

gcc/ChangeLog:

	* ira.cc (update_equiv_regs): Set up ira_reg_equiv for
	valid_combine only when ira_use_lra_p is true.