cgpt: Separate out certain GPT manipluation functions

For kernel NAND support, some vboot/cgptlib functionality is
needed from depthcharge. This patch moves certain function
declarations to a new header in firmware/include and puts
their definitions in a common place.

TEST=make runalltests passes and packages build
BRANCH=none
BUG=chromium:403432

Change-Id: Idd42b1f9f531651d78bb4afb80ca90c24aae93d9
Reviewed-on: https://chromium-review.googlesource.com/224996
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Commit-Queue: Daniel Ehrenberg <dehrenberg@chromium.org>
Tested-by: Daniel Ehrenberg <dehrenberg@chromium.org>
7 files changed