usb: phy: snps: Do not use rext if efuse is programmed

Do not use external resistor if phy parameter is programmed/calibrated
using efuse.

Change-Id: Ib26358320b5f3edf4f5359d44549f52e27c618da
Signed-off-by: Vamsi Krishna Samavedam <vskrishn@codeaurora.org>