drm/hisilicon: Add designware dsi encoder driver

Add DesignWare MIPI DSI Host Controller v1.02 encoder driver
for hi6220 SoC.

v9: Fix module compile error.
v8: None.
v7:
- A few regs define clean up.
v6:
- Change "pclk_dsi" to "pclk".
v5: None.
v4: None.
v3:
- Rename file name to dw_drm_dsi.c
- Make encoder type as DRM_MODE_ENCODER_DSI.
- A few cleanup.
v2:
- Remove abtraction layer.

Signed-off-by: Xinliang Liu <xinliang.liu@linaro.org>
Signed-off-by: Xinwei Kong <kong.kongxinwei@hisilicon.com>
Signed-off-by: Andy Green <andy.green@linaro.org>

drivers/gpu/drm/hisilicon/kirin/Kconfig

@@ -7,3 +7,12 @@ config DRM_HISI_KIRIN
 	help
 	  Choose this option if you have a hisilicon Kirin chipsets(hi6220).
 	  If M is selected the module will be called kirin-drm.
+
+config HISI_KIRIN_DW_DSI
+	tristate "HiSilicon Kirin specific extensions for Synopsys DW MIPI DSI"
+	depends on DRM_HISI_KIRIN
+	select DRM_MIPI_DSI
+	help
+	 This selects support for HiSilicon Kirin SoC specific extensions for
+	 the Synopsys DesignWare DSI driver. If you want to enable MIPI DSI on
+	 hi6220 based SoC, you should selet this option.

drivers/gpu/drm/hisilicon/kirin/Makefile

@@ -2,3 +2,5 @@ kirin-drm-y := kirin_drm_drv.o \
 	       kirin_drm_ade.o
 
 obj-$(CONFIG_DRM_HISI_KIRIN) += kirin-drm.o
+
+obj-$(CONFIG_HISI_KIRIN_DW_DSI) += dw_drm_dsi.o