drm: bridge: synopsys/dw-hdmi: Provide default configuration function for HDMI 2.0 PHY

Currently HDMI 2.0 PHYs do not have a default configuration function.

As *some* of the HDMI 2.0 PHYs have the same register layout as the 3D
PHYs we can provide the same default configuration function for both
and still let user overwrite this with custom configuration function
if needed.

If, for some reason, the PHY is custom or has a register different
register layout then custom configuration function *must* be provided
in order for the system to work correctly. As we prefer the pdata
provided configuration function over the internal one this change
will not make any impact in custom platforms.

Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Tested-by: Mark Yao <mark.yao@rock-chips.com>
Cc: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Mark Yao <mark.yao@rock-chips.com>
Cc: Carlos Palminha <palminha@synopsys.com>
Cc: Heiko Stübner <heiko@sntech.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Link: https://patchwork.freedesktop.org/patch/msgid/185ccf7d4473fa557044732402ca20b3d4007952.1498209896.git.joabreu@synopsys.com