mhi: cntrl: qcom: device requested bandwidth scaling support

Device can request scaling for the PCIe link speeds and width
through MHI. Added support for handling the same.

CRs-Fixed: 2479785
Change-Id: I448d79fe5aa6b8e2e7696938f0085ca5a2b4f358
Acked-by: Bhaumik Vasav Bhatt <bbhatt@qti.qualcomm.com>
Signed-off-by: Sujeev Dias <sdias@codeaurora.org>