This patch enables mmc-hs400-enhanced-strobe for rk3399-evb, so enhanced strobe function will be used if any eMMC 5.1 is probed. Change-Id: If5f30e0d759f7a9850bec82c3d53d9bb26ba8c3d Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>