Squashed 'lib/dtc/' content from commit 65cc4d2

git-subtree-dir: lib/dtc
git-subtree-split: 65cc4d2748a2c2e6f27f1cf39e07a5dbabd80ebf
Added the DTC (libfdt) source tree
[FDT] Added support for updating bootargs in FDT at runtime. (Mirrors U-Boot behaviour).
[BUILD] Add libfdt to build process.
[MISC] Added a general header for BootThunder code.
[CMD] Added cmd_bootm() to mirror the U-Boot bootm command.
[ARCH] ARM - Include platform specific bootm implementation to ARM.
[MISC] Added some defaults to be enabled in BT.
[BT] Updated to latest master, after MMU feature merge.