usb: phy: qusb: Allow support for fused tune2 value correction

Update the TUNE2 parameter by adjusting the programmed tune2 value
with the correction value, if mentioned in dtsi to improve rise/fall times.
In case efuse register value is zero after correction, write previous TUNE2
register value as it is instead of writing hardcoded value. And correction
value should be between [-10 5] in order to take into consideration while
updating TUNE2 register with fused value.

Change-Id: Iaf61705bfd0c7b2cb62de8816c912f05876f001c
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>