[GOLD] Symbol flag for PowerPC64 localentry:0 tracking

[GOLD] Symbol flag for PowerPC64 localentry:0 tracking

This patch provides a flag for PowerPC64 ELFv2 use in class Symbol,
and modifies Sized_target::resolve to return whether the symbol has
been resolved.  If not, normal processing continues.  I use this for
PowerPC64 ELFv2 to keep track of whether a symbol has any definition
with non-zero localentry, in order to disable --plt-localentry for
that symbol.

	PR 21847
	* powerpc.cc (Target_powerpc::is_elfv2_localentry0): Test
	non_zero_localentry.
	(Target_powerpc::resolve): New function.
	(powerpc_info): Set has_resolve for 64-bit.
	* target.h (Sized_target::resolve): Return bool.
	* resolve.cc (Symbol_table::resolve): Continue with normal
	processing when target resolve returns false.
	* symtab.h (Symbol::non_zero_localentry, set_non_zero_localentry):
	New accessors.
	(Symbol::non_zero_localentry_): New flag bit.
	* symtab.cc (Symbol::init_fields): Init non_zero_localentry_.