QcomModulePkg: Add A/B support for Nand Based Targets

Nand flash does not have GPT header and it has only A/B slot for
boot partition. Add support to store a/b partition attributes in
misc cookie and update command line with systemd environment.

Change-Id: Ie07122c9a818a81c9d40077994124de8b106ce5e
6 files changed