objtool/LoongArch: Mark types based on break immediate code

If the break immediate code is 0, it should mark the type as
INSN_TRAP. If the break immediate code is 1, it should mark the
type as INSN_BUG.

While at it, format the code style and add the code comment for nop.

Cc: [e-mail]
Suggested-by: WANG Rui <[e-mail]>
Signed-off-by: Tiezhu Yang <[e-mail]>
Signed-off-by: Huacai Chen <[e-mail]>

tools/objtool/arch/loongarch/decode.c

···
 	if (decode_insn_reg2i16_fomat(inst, insn))
 		return 0;
 
-	if (inst.word == 0)
+	if (inst.word == 0) {
+		/* andi $zero, $zero, 0x0 */
 		insn->type = INSN_NOP;
-	else if (inst.reg0i15_format.opcode == break_op) {
-		/* break */
+	} else if (inst.reg0i15_format.opcode == break_op &&
+		   inst.reg0i15_format.immediate == 0x0) {
+		/* break 0x0 */
+		insn->type = INSN_TRAP;
+	} else if (inst.reg0i15_format.opcode == break_op &&
+		   inst.reg0i15_format.immediate == 0x1) {
+		/* break 0x1 */
 		insn->type = INSN_BUG;
 	} else if (inst.reg2_format.opcode == ertn_op) {
 		/* ertn */