ARM: dts: dra72-evm: drop NAND support

For the existing IOdelay configuration via U-Boot, NAND is
not supported on dra72-evm (both Rev B and Rev C).

Disable it. Commit 46cfc894 ("ARM: dts: dra72-evm: Remove
pinmux configurations for erratum i869") has already removed
pinmuxing for NAND making it unusable.
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/dra72-evm-common.dtsi

@@ -280,7 +280,12 @@ &elm {
 };
 
 &gpmc {
-	status = "okay";
+	/*
+	 * For the existing IOdelay configuration via U-Boot we don't
+	 * support NAND on dra72-evm. Keep it disabled. Enabling it
+	 * requires a different configuration by U-Boot.
+	 */
+	status = "disabled";
 	ranges = <0 0 0x08000000 0x01000000>;	/* minimum GPMC partition = 16MB */
 	nand@0,0 {
 		/* To use NAND, DIP switch SW5 must be set like so: