mpc8548cds: Rework CONFIG_LEGACY usage

This CONFIG option is used in one place, so pick a more direct name and
migrate to Kconfig.  Rework the code slightly.

Cc: Priyanka Jain <priyanka.jain@nxp.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
4 files changed