MIPS: platform: Allow for DTB to be moved during kernel relocation

Add plat_fdt_relocated(void*) API to allow the kernel relocation code to
update platform's information about the DTB location if the DTB had to
be moved due to being placed in a location used by the relocated kernel.

Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14611/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>