usb: dwc3: gadget: pretty print link states
usb: dwc3: gadget: pretty print link states

this makes it slightly easier to read link state
change interrupt logs.

Signed-off-by: Felipe Balbi <94dddeeef08b001e003cce128ddc162a4e2c6cd2@ti.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs