scripts/Makefile.lib: remove bootph-some-ram property from VPL/TPL/SPL

The property isn't useful in VPL/SPL/TPL as it is only for U-Boot proper
pre-reloc, which has its own DTB.

Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
Reviewed-by: Simon Glass <sjg@chromium.org>