usb: phy: Remove reset link training related workaround

On some platform USB super speed phy needs to reset link training to
improve interoperability with different super speed capabale host as
workaround. Remove this workaround as it is no longer required for
newer HW.

Change-Id: I0abd01846cbb9f15b5dbed6dff5ca6f19d40de30
Signed-off-by: Jack Pham <jackp@codeaurora.org>