uboot-phytec

spl: Allow skipping clearing BSS during relocation

On some platform we have sufficient memory available early on to allow
setting up and using a basic BSS prior to relocation. In order to be
able to preserve data written to BSS during early startup add a Kconfig
option allowing to skip the clearing of the BSS section during setting
up of the final environment / relocation.

Signed-off-by: Andreas Dannenberg <dannenberg@ti.com>