usb: dwc3: gadget: do not map/unmap ZLP transfers
usb: dwc3: gadget: do not map/unmap ZLP transfers

If the gadget drivers sends a ZLP we are trying to map this this request
which does not work on all implementations. So we simply skip mapping
it.

Signed-off-by: Sebastian Andrzej Siewior <265264fed90bdf8e813a354375ec16f47ebdb1c5@linutronix.de>
Signed-off-by: Felipe Balbi <94dddeeef08b001e003cce128ddc162a4e2c6cd2@ti.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas