MIPS: math-emu: Allow m{f,t}hc emulation on MIPS R6

The mfhc/mthc instructions are supported on MIPS R6 so emulate
them if needed.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: <stable@vger.kernel.org> # 4.0+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10737/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/math-emu/cp1emu.c

@@ -1137,7 +1137,7 @@ emul:
 			break;
 
 		case mfhc_op:
-			if (!cpu_has_mips_r2)
+			if (!cpu_has_mips_r2_r6)
 				goto sigill;
 
 			/* copregister rd -> gpr[rt] */
@@ -1148,7 +1148,7 @@ emul:
 			break;
 
 		case mthc_op:
-			if (!cpu_has_mips_r2)
+			if (!cpu_has_mips_r2_r6)
 				goto sigill;
 
 			/* copregister rd <- gpr[rt] */