rs6000: Fix the condition with frame_pointer_needed_indeed [PR96072]

rs6000: Fix the condition with frame_pointer_needed_indeed [PR96072]

As PR96072 shows, the code adding REG_CFA_DEF_CFA reg note
makes one assumption that we have emitted one insn which
restores the frame pointer previously.  That part of code
was guarded with flag frame_pointer_needed before, it was
consistent, but it was replaced with flag
frame_pointer_needed_indeed since commit r10-7981.  It
caused ICE due to unexpected NULL insn.

	PR target/96072

gcc/ChangeLog:

	* config/rs6000/rs6000-logue.cc (rs6000_emit_epilogue): Update the
	condition for adding REG_CFA_DEF_CFA reg note with
	frame_pointer_needed_indeed.

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/pr96072.c: New test.