USB: serial: cypress_m8: enable Simply Automated UPB PIM

This is a UPB (Universal Powerline Bus) PIM (Powerline Interface Module)
which allows for controlling multiple UPB compatible devices from Linux
using the standard serial interface.

Based on vendor application source code there are two different models
of USB based PIM devices in addition to a number of RS232 based PIM's.

The vendor UPB application source contains the following USB ID's:

	#define USB_PCS_VENDOR_ID 0x04b4
	#define USB_PCS_PIM_PRODUCT_ID 0x5500

	#define USB_SAI_VENDOR_ID 0x17dd
	#define USB_SAI_PIM_PRODUCT_ID 0x5500

The first set of ID's correspond to the PIM variant sold by Powerline
Control Systems while the second corresponds to the Simply Automated
Incorporated PIM. As the product ID for both of these match the default
cypress HID->COM RS232 product ID it assumed that they both use an
internal variant of this HID->COM RS232 converter hardware. However
as the vendor ID for the Simply Automated variant is different we need
to also add it to the cypress_M8 driver so that it is properly
detected.

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Link: https://lore.kernel.org/r/20200616220403.1807003-1-james.hilliard1@gmail.com
Cc: stable@vger.kernel.org
[ johan: amend VID define entry ]
Signed-off-by: Johan Hovold <johan@kernel.org>