gs101: migrate to bootimg header v4 (second attempt)

We migrate to bootimg header v4 and build the following two vendor
ramdisk fragments.

Type: Platform, Name: "", Contents: Everything but kernel modules
Type: DLKM, Name: "dlkm", Contents: Kernel modules (incl. modules.load etc.)

Bug: 183237066
Change-Id: I626cb87ba8111d0615b80cf981ebc288893a0624
1 file changed