ARM: nomadik: set up MCDATDIR2

This extra data line for high-speed MMC transfers was unrouted,
set it up properly in the dtsi file.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm/boot/dts/ste-nomadik-stn8815.dtsi

@@ -117,7 +117,7 @@ mmcsd {
 			mmcsd_default_mux: mmcsd_mux {
 				mmcsd_default_mux {
 					ste,function = "mmcsd";
-					ste,pins = "mmcsd_a_1";
+					ste,pins = "mmcsd_a_1", "mmcsd_b_1";
 				};
 			};
 			mmcsd_default_mode: mmcsd_default {
@@ -127,9 +127,9 @@ mmcsd_default_cfg1 {
 					ste,output = <0>;
 				};
 				mmcsd_default_cfg2 {
-					/* MCCMDDIR, MCDAT0DIR, MCDAT31DIR */
+					/* MCCMDDIR, MCDAT0DIR, MCDAT31DIR, MCDATDIR2 */
 					ste,pins = "GPIO10_C11", "GPIO15_A12",
-					"GPIO16_C13";
+					"GPIO16_C13", "GPIO23_D15";
 					ste,output = <1>;
 				};
 				mmcsd_default_cfg3 {