drm/omap: move dss_initialized to omapdss-base

omapdss_is_initialized() is used to find out if omapdss has been probed
successfully. This patch moves the related code to the common
omapdss-base module, so that the same support will be there for both
omapdss and omapdss6.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/gpu/drm/omapdrm/dss/dss.c b/drivers/gpu/drm/omapdrm/dss/dss.c
index 4e72d2f..5eb2f12 100644
--- a/drivers/gpu/drm/omapdrm/dss/dss.c
+++ b/drivers/gpu/drm/omapdrm/dss/dss.c
@@ -117,14 +117,6 @@ static const char * const dss_generic_clk_source_names[] = {
 	[DSS_CLK_SRC_HDMI_PLL]	= "HDMI PLL",
 };
 
-static bool dss_initialized;
-
-bool omapdss_is_initialized(void)
-{
-	return dss_initialized;
-}
-EXPORT_SYMBOL(omapdss_is_initialized);
-
 static inline void dss_write_reg(const struct dss_reg idx, u32 val)
 {
 	__raw_writel(val, dss.base + idx.idx);
@@ -1266,7 +1258,7 @@ static int dss_bind(struct device *dev)
 
 	pm_set_vt_switch(0);
 
-	dss_initialized = true;
+	omapdss_set_is_initialized(true);
 
 	return 0;
 
@@ -1290,7 +1282,7 @@ static void dss_unbind(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 
-	dss_initialized = false;
+	omapdss_set_is_initialized(false);
 
 	component_unbind_all(&pdev->dev, NULL);