MLK-14250-5 mx6ulevk: Add plugin boot support

Add plugin.S for plugin boot initialization. Need to set "CONFIG_USE_IMXIMG_PLUGIN"
for this feature.
Add build configurations for the plugin:
mx6ul_14x14_evk_plugin_defconfig
mx6ul_9x9_evk_plugin_defconfig

Signed-off-by: Ye Li <ye.li@nxp.com>
5 files changed