This is based on the following U-Boot commit:
commit 5f4b4f2fed3ab8590c8c06b78642f8c1467acacf
Author: Vincent Palatin <vpalatin@chromium.org>
Date: Mon Dec 5 14:52:22 2011 -0800
ehci: speed up initialization
According to EHCI specification v1.0, the controller should stabilize
the power on a port at most 20 ms after the port power bit transition.
So, we put this setting in the virtual descriptor corresponding field,
(bPwrOn2PwrGood = 10 => 10 x 2ms = 20ms), this saves about 500ms at each
controller initialization/enumeration.
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>