drm/exynos: remove ifdeferry from initialization code

The patch replaces separate calls to driver (de)registration by
loops over the array of drivers. As a result it significantly
decreases number of ifdefs. Additionally it moves device registration
related ifdefs to header file.

Changelog v2:
- Rebased.
- Consider non kms driver in respect to infinite loop issue.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
diff --git a/drivers/gpu/drm/exynos/exynos_drm_drv.h b/drivers/gpu/drm/exynos/exynos_drm_drv.h
index d22e640..3c81c4b 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_drv.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_drv.h
@@ -323,15 +323,14 @@
  */
 void exynos_platform_device_hdmi_unregister(void);
 
-/*
- * this function registers exynos drm ipp platform device.
- */
+#ifdef CONFIG_DRM_EXYNOS_IPP
 int exynos_platform_device_ipp_register(void);
-
-/*
- * this function unregisters exynos drm ipp platform device if it exists.
- */
 void exynos_platform_device_ipp_unregister(void);
+#else
+static inline int exynos_platform_device_ipp_register(void) { return 0; }
+static inline void exynos_platform_device_ipp_unregister(void) {}
+#endif
+
 
 #ifdef CONFIG_DRM_EXYNOS_DPI
 struct exynos_drm_display * exynos_dpi_probe(struct device *dev);
@@ -342,15 +341,13 @@
 static inline int exynos_dpi_remove(struct device *dev) { return 0; }
 #endif
 
-/*
- * this function registers exynos drm vidi platform device/driver.
- */
+#ifdef CONFIG_DRM_EXYNOS_VIDI
 int exynos_drm_probe_vidi(void);
-
-/*
- * this function unregister exynos drm vidi platform device/driver.
- */
 void exynos_drm_remove_vidi(void);
+#else
+static inline int exynos_drm_probe_vidi(void) { return 0; }
+static inline void exynos_drm_remove_vidi(void) {}
+#endif
 
 /* This function creates a encoder and a connector, and initializes them. */
 int exynos_drm_create_enc_conn(struct drm_device *dev,