doc: usb: ci-hdrc-usb2: add property over-current-active-high

Adding over-current-active-high to indicate the over current flag
is high active as typically we use active low for over current
polarity.

Signed-off-by: Li Jun <jun.li@nxp.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>
Acked-by: Rob Herring <robh@kernel.org>