feat(plat/nxp/lx2): add SUPPORTED_BOOT_MODE definition

Add macro of SUPPORTED_BOOT_MODE for board lx2160ardb, lx2160aqds,
lx2162aqds.

Signed-off-by: Biwen Li <biwen.li@nxp.com>
Signed-off-by: Jiafei Pan <Jiafei.Pan@nxp.com>
Change-Id: I4451ca030eca79c9bc5fee928eec497a7f0e878c
3 files changed