This patch adds delay P0 to P1/P2/P3 quirk for U2/U2/U3, and some special
platforms can configure that if it is needed.

[ balbi@ti.com : added DeviceTree binding documentation ]
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>