msm: qpnp-revid: Add REVID driver

Add the REVID device driver. The REVID driver will print out the PMIC
revision at probe time.

Change-Id: I2769b8a315e83bd4b60841e0b4d3ade363cd0c29
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>
4 files changed