xtensa: gas: put .literal_position at section start

xtensa: gas: put .literal_position at section start

Provide literal position at the beginning of each section for literal
space reserved by relaxations when text-section-literals or
auto-litpools options are used. Remove code that adds fill frag to the
literal section for every .literal_position directive to avoid creation
of empty literal sections.

Fix auto-litpools tests that got literal pool address changes.

gas/
2019-04-11  Max Filippov  <jcmvbkbc@gmail.com>

	* config/tc-xtensa.c (xtensa_is_init_fini): Add declaration.
	(xtensa_mark_literal_pool_location): Don't add fill frag to literal
	section that records literal pool location.
	(md_begin): Call xtensa_mark_literal_pool_location when text
	section literals or auto litpools are used.
	(xtensa_elf_section_change_hook): Call
	xtensa_mark_literal_pool_location when text section literals or
	auto litpools are used, there's no literal pool location defined
	for the current section and it's not .init or .fini.
	* testsuite/gas/xtensa/auto-litpools-first1.d: Fix up addresses.
	* testsuite/gas/xtensa/auto-litpools-first2.d: Likewise.
	* testsuite/gas/xtensa/auto-litpools.d: Likewise.