Implements customer configuration of kernel options to control
spectre/meltdown related kernel options. Default (with "nopti
nospectre_v2" options) can be changed to "" using
system modify -S spectre_meltdown_all
Change-Id: I183a22fa681e6524415558c0009aa8786418cc07
Signed-off-by: Jack Ding <jack.ding@windriver.com>