drm/imx: remove imx_drm_encoder_get_mux_id

It is replaced by drm_of_encoder_active_port_id.

Suggested-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
index 22ac482..0ec3b1d 100644
--- a/drivers/gpu/drm/imx/imx-ldb.c
+++ b/drivers/gpu/drm/imx/imx-ldb.c
@@ -19,6 +19,7 @@
 #include <drm/drmP.h>
 #include <drm/drm_fb_helper.h>
 #include <drm/drm_crtc_helper.h>
+#include <drm/drm_of.h>
 #include <drm/drm_panel.h>
 #include <linux/mfd/syscon.h>
 #include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
@@ -215,7 +216,7 @@
 	struct imx_ldb_channel *imx_ldb_ch = enc_to_imx_ldb_ch(encoder);
 	struct imx_ldb *ldb = imx_ldb_ch->ldb;
 	int dual = ldb->ldb_ctrl & LDB_SPLIT_MODE_EN;
-	int mux = imx_drm_encoder_get_mux_id(imx_ldb_ch->child, encoder);
+	int mux = drm_of_encoder_active_port_id(imx_ldb_ch->child, encoder);
 
 	drm_panel_prepare(imx_ldb_ch->panel);
 
@@ -265,7 +266,7 @@
 	int dual = ldb->ldb_ctrl & LDB_SPLIT_MODE_EN;
 	unsigned long serial_clk;
 	unsigned long di_clk = mode->clock * 1000;
-	int mux = imx_drm_encoder_get_mux_id(imx_ldb_ch->child, encoder);
+	int mux = drm_of_encoder_active_port_id(imx_ldb_ch->child, encoder);
 
 	if (mode->clock > 170000) {
 		dev_warn(ldb->dev,