sanity.bbclass: vmdk and live can't be built together
Both vmdk and live use syslinux, but they have different/conflicted
configurations, the main conflictions are:
vmdk live
SYSLINUX_ROOT root=/dev/sda2 root=/dev/ram0
SYSLINUX_LABELS boot boot install
INITRD No yes
So it would make the boot menu strange and vmdk can't be boot, we need
add a few extra vars to fix the problem such as SYSLINUX_ROOT_VMDK
SYSLINUX_ROOT_LIVE, but that needs a lot of changes in the code, so just
add a sanity checking for it.
[YOCTO #6889]
Signed-off-by: Robert Yang <liezhi.yang@windriver.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
