usb: gadget: fusb300_udc: bug fix of not doing idma reset for each time

Enter IDMA_RESET only when the controller has been reset or
the device has been plugged in to or out from a host. In
IDMA_RESET, we should disable the corresponding PRD interrupt.
Also there is a redundant space eliminated.

fusb300_udc driver is tested on FARADAY platform a369 with
FUSB300 FPGA v1.8

Signed-off-by: Yuan-Hsin Chen <yhchen@faraday-tech.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>