Re: Fix minor NDS32 renaming snafu

Re: Fix minor NDS32 renaming snafu

Some extern declarations differ in constnes to their definitions too.
Let's make sure this sort of thing doesn't happen again, but putting
the externs in a header where they belong.

gas/
	* config/tc-nds32.c (nds32_keyword_gpr): Don't declare.
	(md_begin): Constify k.
opcodes/
	* nds32-dis.c (nds32_find_reg_keyword): Constify arg and return.
	(nds32_parse_audio_ext, nds32_parse_opcode): Constify psys_reg.
	(nds32_field_table, nds32_opcode_table, nds32_keyword_table),
	(nds32_opcodes, nds32_operand_fields, nds32_keywords),
	(nds32_keyword_gpr): Move declarations to..
	* nds32-asm.h: ..here, constifying to match definitions.