ARM: davinci: da850: add mmc DT entries

Add DT entry for MMC. Also add entry for pinmux information.
Tested:
1) Without GPIO card detection and EDMA support as DT support for
   GPIO and EDMA are yet come.
2) By creating/deleting files and mounting/unmounting the partition.

Signed-off-by: Manjunathappa, Prakash <prakash.pm@ti.com>
Cc: linux-mmc@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: davinci-linux-open-source@linux.davincidsp.com
Cc: devicetree-discuss@lists.ozlabs.org
Cc: cjb@laptop.org
Cc: Sekhar Nori <nsekhar@ti.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>

arch/arm/boot/dts/da850-evm.dts

@@ -43,6 +43,13 @@
 		wdt: wdt@1c21000 {
 			status = "okay";
 		};
+		mmc0: mmc@1c40000 {
+			max-frequency = <50000000>;
+			bus-width = <4>;
+			status = "okay";
+			pinctrl-names = "default";
+			pinctrl-0 = <&mmc0_pins>;
+		};
 	};
 	nand_cs3@62000000 {
 		status = "okay";