bus: mhi: host: pci_generic: Add HP variant of T99W175

The Foxconn T99W175 modem has an HP variant, which has
the following output from lspci:

01:00.0 Wireless controller [0d40]: Device 03f0:0a6c

It also has some HP-specific serial numbers on the
metal case. It works well with this driver, so add
support for this to the pci_generic driver.

Signed-off-by: Song Fuchang <song.fc@gmail.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
[mani: manually applied the patch]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>