or1k: add support for l.swa/l.lwa atomic instructions

This adds support for the load-link/store-conditional
l.lwa/l.swa atomic instructions.
The support is added in such way, that the cpu description not
only describes the mnemonics, but also the functionality.

A couple of fixes to typos in nearby/related code are also snuck
into this.

cpu/
	* or1korbis.cpu (h-atomic-reserve): New hardware.
	(h-atomic-address): Likewise.
	(insn-opcode): Add opcodes for LWA and SWA.
	(atomic-reserve): New operand.
	(atomic-address): Likewise.
	(l-lwa, l-swa): New instructions.
	(l-lbs): Fix typo in comment.
	(store-insn): Clear atomic reserve on store to atomic-address.
	Fix register names in fmt field.

opcodes/
	* or1k-desc.c: Regenerated.
	* or1k-desc.h: Likewise.
	* or1k-opc.c: Likewise.
	* or1k-opc.h: Likewise.
	* or1k-opinst.c: Likewise.