am335x, guardian: load env from NAND

- As there is a requirement to store certain data, we need a persistent
    storage in u-boot. Hence, we need to save env in NAND

  - Add default Guardian environment variables

  - Update partition table:
    - Reserve some space for experimentation, this ensures proper
      backwards compatibility

  - Update defconfig accordingly

Signed-off-by: Moses Christopher <BollavarapuMoses.Christopher@in.bosch.com>
diff --git a/arch/arm/dts/am335x-guardian.dts b/arch/arm/dts/am335x-guardian.dts
index b554be9..7e70a96 100644
--- a/arch/arm/dts/am335x-guardian.dts
+++ b/arch/arm/dts/am335x-guardian.dts
@@ -202,8 +202,33 @@
 		};
 
 		partition@6 {
+			label = "u-boot-2";
+			reg = <0x300000 0x100000>;
+		};
+
+		partition@7 {
+			label = "u-boot-2.backup1";
+			reg = <0x400000 0x100000>;
+		};
+
+		partition@8 {
+			label = "u-boot-env";
+			reg = <0x500000 0x40000>;
+		};
+
+		partition@9 {
+			label = "u-boot-env.backup1";
+			reg = <0x540000 0x40000>;
+		};
+
+		partition@10 {
+			label = "splash-screen";
+			reg = <0x580000 0x40000>;
+		};
+
+		partition@11 {
 			label = "UBI";
-			reg = <0x300000 0x1fd00000>;
+			reg = <0x5c0000 0x1fa40000>;
 		};
 	};
 };