switch: qcom: enable PCI device and set BME

During the PCI probe for each port, enable its PCI device so that
it's ready for its driver. Also, set the bus master so that
any traffic from downstream can be forward to upstream.

Add PCI remove to handle the clean up.

Change-Id: I959ab50ebba2b4351590f83e8e1b780a670ca730
Signed-off-by: Tony Truong <truong@codeaurora.org>