PCI: dwc: all: Modify dbi accessors to take dbi_base as argument

dwc has 2 dbi address space labeled dbics and dbics2. The existing helper
to access dbi address space can access only dbics. However dbics2 has to
be accessed for programming the BAR registers in the case of EP mode. This
is in preparation for adding EP mode support to dwc driver.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Niklas Cassel <niklas.cassel@axis.com>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Joao Pinto <Joao.Pinto@synopsys.com>