drm/ingenic: depend on COMMON_CLK to fix compile tests

The Ingenic DRM uses Common Clock Framework thus it cannot be built on
platforms without it (e.g. compile test on MIPS with RALINK and
SOC_RT305X):

    /usr/bin/mips-linux-gnu-ld: drivers/gpu/drm/ingenic/ingenic-drm-drv.o: in function `ingenic_drm_bind.isra.0':
    ingenic-drm-drv.c:(.text+0x1600): undefined reference to `clk_get_parent'
    /usr/bin/mips-linux-gnu-ld: ingenic-drm-drv.c:(.text+0x16b0): undefined reference to `clk_get_parent'
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20201116175301.402787-2-krzk@kernel.org

drivers/gpu/drm/ingenic/Kconfig

@@ -4,6 +4,7 @@ config DRM_INGENIC
 	depends on DRM
 	depends on CMA
 	depends on OF
+	depends on COMMON_CLK
 	select DRM_BRIDGE
 	select DRM_PANEL_BRIDGE
 	select DRM_KMS_HELPER