pci: msm: msm_pcie_iatu_config API clean

Get rid of access to pciedev_table. Update data type
for bdf from unsigned long to u32. Remove support for
viewport.

Change-Id: I2bb27eab2b37a640c468377f5d4993d67b5979d0
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>