drm/imx: turn remaining container_of macros into inline functions

This allows the compiler to do type checking.

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 9ac8335..00d67b5 100644
--- a/drivers/gpu/drm/imx/imx-ldb.c
+++ b/drivers/gpu/drm/imx/imx-ldb.c
@@ -51,8 +51,6 @@
 #define LDB_DI1_VS_POL_ACT_LOW		(1 << 10)
 #define LDB_BGREF_RMODE_INT		(1 << 15)
 
-#define con_to_imx_ldb_ch(x) container_of(x, struct imx_ldb_channel, connector)
-
 struct imx_ldb;
 
 struct imx_ldb_channel {
@@ -70,6 +68,11 @@
 	u32 bus_format;
 };
 
+static inline struct imx_ldb_channel *con_to_imx_ldb_ch(struct drm_connector *c)
+{
+	return container_of(c, struct imx_ldb_channel, connector);
+}
+
 static inline struct imx_ldb_channel *enc_to_imx_ldb_ch(struct drm_encoder *e)
 {
 	return container_of(e, struct imx_ldb_channel, encoder);