the boot parameters from initarm first thing. parse_boot_param parses
the boot arguments and converts them to the /boot/loader metadata the
rest of the kernel uses. parse_boot_param is a weak alias to
fake_preload_metadata, which all the platforms use now, but may become
more extensive in the future.
Since it is a weak symbol, specific boards may define their own
parse_boot_param to interface to custom boot loaders.
Reviewed by: cognet@, Ian Lapore