rk3399 dwc3 has a problem that USB 2.0 MAC lineState not
reflect the expected line state (J) during transmission.
Add this quirk to add the ipgap between (tkn to tkn/data)
with 40 bit times of TXENDDELAY, and linestate is ignored
during this 40 bit times delay.
Change-Id: Ife9d46dbf2a8d4a8faa2fc20bfad442d6bb88a05 Signed-off-by: William Wu <william.wu@rock-chips.com>