phy: add PHY_MODE_PCIE_BIFURCATION support

Bifurcation mode is tunable lanes which could be devided
into different individual combination.

Change-Id: Ie6a10694d3c4fd5da1a5673d58424de797f3622b
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>

include/linux/phy/phy.h

@@ -45,6 +45,7 @@ enum phy_mode {
 	PHY_MODE_VIDEO_TTL,
 	PHY_MODE_PCIE_RC,
 	PHY_MODE_PCIE_EP,
+	PHY_MODE_PCIE_BIFURCATION,
 	PHY_MODE_GVI,
 	PHY_MODE_HDMI,
 };