power: pm8921-charger: PMIC version check for workarounds

Since the revision registers across different PMIC chips
may match up some workarounds may be applied to chips
that do not require them and cause issues.

Fix this by adding version checks to these workarounds
to make sure that the workarounds are applied to the correct
PMIC version.

Change-Id: I8af031570466a88656c89ee7764f78c5ec14d247
Signed-off-by: David Keitel <dkeitel@codeaurora.org>