usb: renesas: pipe: convert a long if into a XOR operation

This is just a minor optimization for the long
if we have on the driver.

When we want to check that one input is true
and the other must be false, the bitwise XOR
operator will achieve that for us.

Tested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>