Add system register and embedded debug register support.

Add system register and embedded debug register support.
Add two more as test files for user special and system register.
Fix typo.

2013-12-17  Kuan-Lin Chen  <kuanlinchentw@gmail.com>

	* gas/nds32/nds32.exp: Add system and user special register tests.
	* gas/nds32/sys-reg.s: New test.
	* gas/nds32/sys-reg.d: Likewise.
	* gas/nds32/usr-spe-reg.s: Likewise.
	* gas/nds32/usr-spe-reg.d: Likewise.
	* gas/nds32/alu-2.d: Delete the new blank line at EOF.
	* gas/nds32/br-1.d: Likewise.
	* gas/nds32/br-2.d: Likewise.
	* gas/nds32/ji-jr.d: Likewise.
	* gas/nds32/lsi.d: Likewise.
	* nds32-dis.c (sr_map): Add system register table for disassembling.
	(usr_map): Fix typo.
	* nds32-asm.c (keyword_sr): Add embedded debug registers.