Rework MIPS nop-insertion code, add -mfix-vr4130 [9/11]

[Eric Christopher]

> 
> 	* config/tc-mips.h (mips_flush_pending_output): Delete.
> 	(mips_emit_delays): Declare.
> 	(md_flush_pending_output): Use mips_emit_delays.
> 	* config/tc-mips.c (mips_no_prev_insn): Remove parameter; always forget
> 	the previous instructions.
> 	(md_begin, append_insn, md_parse_option): Update callers.
> 	(mips_emit_delay): Remove parameter.  Move INSNS != 0 code to
> 	start_noreorder.
> 	(mips_align, s_change_sec, s_cons, s_float_cons, s_gpword)
> 	(s_gpdword): Update callers.
> 	(start_noreorder, end_noreorder): New functions.
> 	(macro, macro2, mips16_macro, s_mipsset): Use them instead of
> 	manipulating mips_opts or prev_nop_frag directly.
> 	(mips_flush_pending_output): Delete.

OK mainline and branch.

-eric