usb: Replace ITUNERNET vendor with MICROCHIP and improve product names

[jrtc27]

Summary

These Mini-Box LCDs are using Microchip components and sub-licensed product
IDs. Whilst here, update the constant names and descriptions for the products
to use the names listed on the manufacturer's website rather than vague ones.
The picoLCD 4x20 is named that on the manufacturer's website so prefer that
name, even though linux-usb.org lists it with the numbers reversed as one might
expect.