devicetree: phy: rockchip-emmc add output-tapdelay-select

Update the rockchip-emmc-phy.txt and add the u32 property
'output-tapdelay-select'. This allow to set the otapdlysec register.

Tested with our customized rk3399 board to tune eMMC.

Signed-off-by: Chris Ruehl <chris.ruehl@gtsys.com.hk>
Link: https://lore.kernel.org/r/20201202082507.3536-3-chris.ruehl@gtsys.com.hk


Signed-off-by: Vinod Koul <vkoul@kernel.org>