[ARC] Test against frame_pointer_needed in arc_can_eliminate.

[ARC] Test against frame_pointer_needed in arc_can_eliminate.

arc_can_eliminate is using arc_frmae_pointer_required() which is wrong
as the frame_pointer_needed can be set on different conditions. Fix it
by calling arc_frame_pointer_needed().

gcc/
2017-06-01  Claudiu Zissulescu  <claziss@synopsys.com>

	* config/arc/arc.c (arc_can_eliminate): Test against
	arc_frame_pointer_needed.

From-SVN: r248782