packaging: Packaging updates for installation in boot partition
Various updates to make the kernel image more usable/familiar on
the Renesas plaform. This is a squash commit of the following:
packaging: Install uImage instead of vmlinuz when available
packaging: Make initrd installation conditional
packaging: Diable gummiboot section of post-install script
packaging: Create link to "latest" kernel in /lib/modules
packaging: Move upstream tag to .gbs.conf
packaging: support modules
Change-Id: Ia5d6d853b1794fd28fa8bbc5f55178fb18ae26de