Adjust the symbol for SECTION_LINK_ORDER linked_to section [PR99889]

Adjust the symbol for SECTION_LINK_ORDER linked_to section [PR99889]

As discussed in PR98125, -fpatchable-function-entry with
SECTION_LINK_ORDER support doesn't work well on powerpc64
ELFv1 because the filled "Symbol" in

  .section name,"flags"o,@type,Symbol

sits in .opd section instead of in the function_section
like .text or named .text*.

Since we already generates one label LPFE* which sits in
function_section of current_function_decl, this patch is
to reuse it as the symbol for the linked_to section.  It
avoids the above ABI specific issue when using the symbol
concluded from current_function_decl.

Besides, with this support some previous workarounds can
be reverted.

	PR target/99889

gcc/ChangeLog:

	* config/rs6000/rs6000.cc (rs6000_print_patchable_function_entry):
	Adjust to call function default_print_patchable_function_entry.
	* targhooks.cc (default_print_patchable_function_entry_1): Remove and
	move the flags preparation ...
	(default_print_patchable_function_entry): ... here, adjust to use
	current_function_funcdef_no for label no.
	* targhooks.h (default_print_patchable_function_entry_1): Remove.
	* varasm.cc (default_elf_asm_named_section): Adjust code for
	__patchable_function_entries section support with LPFE label.

gcc/testsuite/ChangeLog:

	* g++.dg/pr93195a.C: Remove the skip on powerpc*-*-* 64-bit.
	* gcc.target/aarch64/pr92424-2.c: Adjust LPFE1 with LPFE0.
	* gcc.target/aarch64/pr92424-3.c: Likewise.
	* gcc.target/i386/pr93492-2.c: Likewise.
	* gcc.target/i386/pr93492-3.c: Likewise.
	* gcc.target/i386/pr93492-4.c: Likewise.
	* gcc.target/i386/pr93492-5.c: Likewise.