mhi: cntrl: qcom: disable pcie low power mode during bw scaling

Keep the PCIe link in L0 state during bandwidth scaling based
on speed switching requirements. Add a disable depth counter to
ensure all votes are considered before changing low power state
as multiple callers can toggle the state.

CRs-Fixed: 2439952
Change-Id: I826936d7b16375adb461db65fb58356fa5dda113
Acked-by: Bhaumik Vasav Bhatt <bbhatt@qti.qualcomm.com>
Signed-off-by: Sujeev Dias <sdias@codeaurora.org>