drm/imx: imx-tve: depend on COMMON_CLK

Since the TVE provides a clock to the DI, the driver can only be
compiled if the common clock framework is enabled. With the COMMON_CLK
dependency in place, it will be possible to allow building the other
parts of imx-drm under COMPILE_TEST on architectures that do not select
the common clock framework.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpu/drm/imx/Kconfig b/drivers/gpu/drm/imx/Kconfig
index c9e439c..c554284 100644
--- a/drivers/gpu/drm/imx/Kconfig
+++ b/drivers/gpu/drm/imx/Kconfig
@@ -18,6 +18,7 @@
 config DRM_IMX_TVE
 	tristate "Support for TV and VGA displays"
 	depends on DRM_IMX
+	depends on COMMON_CLK
 	select REGMAP_MMIO
 	help
 	  Choose this to enable the internal Television Encoder (TVe)