ArmPkg/BdsLinuxFdt.c: Fix creation of 'cpu' and 'psci' device tree nodes.

ArmPkg/BdsLinuxFdt.c: Fix creation of 'cpu' and 'psci' device tree nodes.

* Fix name of 'device_type' and 'migrate' properties.
* Fix 'reg' property. It is supposed to contain the CPU MPIDR of the
  CPU being described.
* Fix byte ordering of data in 'psci' node.
* Fix some problems regarding the size of data. In a number of places
  it was assumed data would be 32-bits wide.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <olivier.martin@arm.com>
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14351 6f19259b-4bc3-4df7-8a09-765794883524