[RS6000] Emit inline PLT when -mno-tls-markers

[RS6000] Emit inline PLT when -mno-tls-markers

I restricted output of inline PLT sequences to when TLS marker relocs
were also available, which is obviously true when just considering
assembler support.  However, there is a -mno-tls-markers option to
disable emitting the marker relocs.  Currently that option also
disables inline PLT sequences, which is a bug (*).  This patch fixes
that problem.

*) To be honest, it was a deliberate bug.  I didn't want to have to
deal with inline PLT __tls_get_addr sequences lacking the marker
relocs in the linker, but it turns out the existing linker support for
old-style __tls_get_addr calls works reasonably well.

	* config/rs6000/rs6000.c (rs6000_indirect_call_template_1),
	(rs6000_pltseq_template): Guard output of TLS markers with
	TARGET_TLS_MARKERS.
	(rs6000_longcall_ref, rs6000_call_aix, rs6000_call_sysv),
	(rs6000_sibcall_sysv): Ignore TARGET_TLS_MARKERS when deciding
	to use inline PLT sequences.
	* config/rs6000/rs6000.md (pltseq_tocsave_<mode>),
	(pltseq_plt16_ha_<mode>, pltseq_plt16_lo_<mode>),
	(pltseq_mtctr_<mode>): Don't test TARGET_TLS_MARKERS in predicate.

From-SVN: r268519