mhi: cntrl: qcom: store PCIe BAR address in controller structure

Store PCIe base address register (BAR) in MHI controller structure
for clients to use.

CRs-Fixed: 2341097
Change-Id: Ib1d71c633fe0067873dd3ab4af6804cbd0281a7b
Acked-by: Bhaumik Vasav Bhatt <bbhatt@qti.qualcomm.com>
Signed-off-by: Sujeev Dias <sdias@codeaurora.org>