refactor(plat/nxp/common): moved soc make-variables to new soc_common_def.mk

Move some soc make variables to new soc_common_def.mk,
then it can be reused by other platforms.

Signed-off-by: Jiafei Pan <Jiafei.Pan@nxp.com>
Change-Id: Ia30bd332c95b6475f1cfee2f03a8ed3892a9568d
1 file changed