rpi3: Remove broken support of RESET_TO_BL31

There is no way to boot BL31 at the addresses specified in the platform
memory map unless an extra loader is used at address 0x00000000. It is
better to remove it to prevent confusion. Having it enabled was a bug.

Change-Id: I3229fbc080f5996cff47efce8e799bae94e0d5cb
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
3 files changed