serial: 8250_pci: Add support for Pericom PI7C9X795[1248]

[ Upstream commit 89c043a6 ]

Pericom PI7C9X795[1248] are Uno/Dual/Quad/Octal UART devices, this
patch enables them, also defines PCI_VENDOR_ID_PERICOM here.

Signed-off-by: Adam Lee <adam.lee@canonical.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[Lee: Back-ported to solve an build dependency]
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: If75c62bce8bb4e7b208aeda418455eb290c82091