power: qpnp-fg-gen3: synchronize ESR extraction control configuration

Currently, ESR extraction control is configured from two paths.
First is invoked when Qnovo is enabled or disabled. Second is
invoked when the pulse train is done and ESR measurement is
requested. When the latter is run, there is a sleep time of 1.5
seconds that is essential for allowing FG to do ESR measurement.
However in that time window, if Qnovo is disabled for some reason
then ESR extraction control will be kept disabled unexpectedly.

Fix this by protecting both the paths using a mutex lock as well
as checking for qnovo enable status before disabling ESR
extraction control after measuring ESR.

Change-Id: Ib93539071724a1ce59d198074854a8a9c5fd3ab3
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>