MIPS: OCTEON: Use correct instruction to read 64-bit COP0 register

Use dmfc0/dmtc0 instructions for reading CvmMemCtl COP0 register,
its a 64-bit wide.
Signed-off-by: Chandrakala Chavva <cchavva@caviumnetworks.com>
Signed-off-by: Aleksey Makarov <aleksey.makarov@auriga.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: David Daney <david.daney@cavium.com>
Patchwork: https://patchwork.linux-mips.org/patch/8936/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/octeon_switch.S

@@ -80,7 +80,7 @@
 1:
 #if CONFIG_CAVIUM_OCTEON_CVMSEG_SIZE > 0
 	/* Check if we need to store CVMSEG state */
-	mfc0	t0, $11,7	/* CvmMemCtl */
+	dmfc0	t0, $11,7	/* CvmMemCtl */
 	bbit0	t0, 6, 3f	/* Is user access enabled? */
 
 	/* Store the CVMSEG state */
@@ -104,9 +104,9 @@
 	.set reorder
 
 	/* Disable access to CVMSEG */
-	mfc0	t0, $11,7	/* CvmMemCtl */
+	dmfc0	t0, $11,7	/* CvmMemCtl */
 	xori	t0, t0, 0x40	/* Bit 6 is CVMSEG user enable */
-	mtc0	t0, $11,7	/* CvmMemCtl */
+	dmtc0	t0, $11,7	/* CvmMemCtl */
 #endif
 3: