QcomModulePkg: allow retrieving oem partition guid

"oem" is a partition where device specific values are stored,
such as "serial number", "hardware revision", ...

This change allows retrieving the partition guid of "oem",
which will be used in future changes.

Change-Id: Ic0b70a312d22cc0eaaf4eaad50c2997de45a6e7d
Signed-off-by: Alexander Martinz <amartinz@shiftphones.com>
4 files changed