video: rockchip: dw_mipi_dsi: Use generic_phy_valid() helper

The documentation for struct phy state that "The content of the
structure is managed solely by the PHY API and PHY drivers".

Change to use the generic_phy_valid() helper to check if phy is valid.

Fixes: b7d8d40346f2 ("video: rockchip: dw_mipi_dsi: Fix external phy existence check")
Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/drivers/video/rockchip/dw_mipi_dsi_rockchip.c b/drivers/video/rockchip/dw_mipi_dsi_rockchip.c
index 0852b53..1a5ab78 100644
--- a/drivers/video/rockchip/dw_mipi_dsi_rockchip.c
+++ b/drivers/video/rockchip/dw_mipi_dsi_rockchip.c
@@ -377,7 +377,7 @@
 	struct dw_rockchip_dsi_priv *dsi = dev_get_priv(dev);
 	int ret, i, vco;
 
-	if (dsi->phy.dev) {
+	if (generic_phy_valid(&dsi->phy)) {
 		ret = generic_phy_configure(&dsi->phy, &dsi->phy_opts);
 		if (ret) {
 			dev_err(dsi->dsi_host,
@@ -559,7 +559,7 @@
 	}
 
 	/* for external phy only the mipi_dphy_config is necessary */
-	if (dsi->phy.dev) {
+	if (generic_phy_valid(&dsi->phy)) {
 		phy_mipi_dphy_get_default_config(timings->pixelclock.typ  * 10 / 8,
 						 bpp, lanes,
 						 &dsi->phy_opts);
@@ -859,7 +859,7 @@
 	}
 
 	/* Get a ref clock only if not using an external phy. */
-	if (priv->phy.dev) {
+	if (generic_phy_valid(&priv->phy)) {
 		dev_dbg(dev, "setting priv->ref to NULL\n");
 		priv->ref = NULL;