ARM: implement relocation for ARM V7 (OMAP)

Change the implementation for ARM V7 to relocate the code to an
arbitrary address in RAM.

Adapt the Beagle board (Cortex A8) to test the changes.

Portions of this work were supported by funding from
the CE Linux Forum.

Signed-off-by: Heiko Schocher <hs@denx.de>