drm/exynos: Fix PTN3460 dependency

The following configuration options combination:

CONFIG_DRM_EXYNOS_DP=y
CONFIG_DRM_PTN3460=m

currently leads to the following linker failure:

drivers/built-in.o: In function `exynos_drm_attach_lcd_bridge':
.../drivers/gpu/drm/exynos/exynos_dp_core.c:1004:
undefined reference to `ptn3460_init'

This is because ptn3460_init can't be implemented in a module while
its caller is built into the kernel. So add the proper dependency in
Kconfig so that the above can't happen.

I moved DRM_PTN3460 earlier in Kconfig, next to the I2C helper module
section, so that the user has a chance to select it before moving to
the Exynos-specific section.

IMHO the proper way to solve the problem would be to turn ptn3460 into
a clean I2C driver, similar to the other I2C helper chip drivers. It's
the only way to not sink into impossible-to-guess dependencies. Then
ptn3460 could even be moved together with the other I2C helper chip
drivers.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/Kconfig

@@ -83,6 +83,8 @@ config DRM_KMS_CMA_HELPER
 
 source "drivers/gpu/drm/i2c/Kconfig"
 
+source "drivers/gpu/drm/bridge/Kconfig"
+
 config DRM_TDFX
 	tristate "3dfx Banshee/Voodoo3+"
 	depends on DRM && PCI
@@ -199,5 +201,3 @@ source "drivers/gpu/drm/msm/Kconfig"
 source "drivers/gpu/drm/tegra/Kconfig"
 
 source "drivers/gpu/drm/panel/Kconfig"
-
-source "drivers/gpu/drm/bridge/Kconfig"

drivers/gpu/drm/exynos/Kconfig

@@ -50,7 +50,7 @@ config DRM_EXYNOS_DSI
 
 config DRM_EXYNOS_DP
 	bool "EXYNOS DRM DP driver support"
-	depends on DRM_EXYNOS && ARCH_EXYNOS
+	depends on DRM_EXYNOS && ARCH_EXYNOS && (DRM_PTN3460=n || DRM_PTN3460=y || DRM_PTN3460=DRM_EXYNOS)
 	default DRM_EXYNOS
 	help
 	  This enables support for DP device.