MIPS: Emulate the new MIPS R6 BOVC, BEQC and BEQZALC instructions

MIPS R6 uses the <R6 ADDI opcode for the new BOVC, BEQC and
BEQZALC instructions.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
diff --git a/arch/mips/kernel/branch.c b/arch/mips/kernel/branch.c
index 1a0a30e..80a073c 100644
--- a/arch/mips/kernel/branch.c
+++ b/arch/mips/kernel/branch.c
@@ -790,6 +790,17 @@
 		regs->cp0_epc += 8;
 		break;
 #endif
+	case cbcond0_op:
+		/* Only valid for MIPS R6 */
+		if (!cpu_has_mips_r6) {
+			ret = -SIGILL;
+			break;
+		}
+		/* Compact branches: bovc, beqc, beqzalc */
+		if (insn.i_format.rt && !insn.i_format.rs)
+			regs->regs[31] = epc + 4;
+		regs->cp0_epc += 8;
+		break;
 	}
 
 	return ret;