powerpc: Enable device tree support for T1024RDB

Add device tree for T1024RDB board and enable CONFIG_OF_CONTROL
so that device tree can be compiled.
Update board README for device tree usage.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Reviewed-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
diff --git a/arch/powerpc/dts/e5500_power_isa.dtsi b/arch/powerpc/dts/e5500_power_isa.dtsi
new file mode 100644
index 0000000..0a0943b0
--- /dev/null
+++ b/arch/powerpc/dts/e5500_power_isa.dtsi
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0+ OR X11
+/*
+ * e5500 Power ISA Device Tree Source (include)
+ *
+ * Copyright 2012 Freescale Semiconductor Inc.
+ * Copyright 2019 NXP
+ */
+
+/ {
+	cpus {
+		power-isa-version = "2.06";
+		power-isa-b;		// Base
+		power-isa-e;		// Embedded
+		power-isa-atb;		// Alternate Time Base
+		power-isa-cs;		// Cache Specification
+		power-isa-ds;		// Decorated Storage
+		power-isa-e.ed;		// Embedded.Enhanced Debug
+		power-isa-e.pd;		// Embedded.External PID
+		power-isa-e.hv;		// Embedded.Hypervisor
+		power-isa-e.le;		// Embedded.Little-Endian
+		power-isa-e.pm;		// Embedded.Performance Monitor
+		power-isa-e.pc;		// Embedded.Processor Control
+		power-isa-ecl;		// Embedded Cache Locking
+		power-isa-exp;		// External Proxy
+		power-isa-fp;		// Floating Point
+		power-isa-fp.r;		// Floating Point.Record
+		power-isa-mmc;		// Memory Coherence
+		power-isa-scpm;		// Store Conditional Page Mobility
+		power-isa-wt;		// Wait
+		power-isa-64;		// 64-bit
+		fsl,eref-deo;		// Data Cache Extended Operations
+		mmu-type = "power-embedded";
+	};
+};