drm/i915: Add support for Generic MIPI panel driver

This driver makes use of the generic panel information from the VBT.
Panel information is classified into two - panel configuration and panel
power sequence which is unique to each panel. The generic driver uses the
panel configuration and sequence parsed from VBT block #52 and #53

v2: Address review comments by Jani
    - Move all of the things in driver c file from header
    - Make all functions static
    - Make use of video/mipi_display.c instead of redefining
    - Null checks during sequence execution

v3: Address review comments by Damien
    - Rename the panel driver file as intel_dsi_panel_vbt.c
    - Fix style changes as suggested
    - Correct comments for lp->hs and hs->lp count calculations
    - General updating comments to have more clarity
    - using max() instead of ternary operator
    - Fix names (ui_num, ui_den) while using UI in calculations
    - compute max of lp_to_hs switch and hs_to_lp switch while computing
      hs_lp_switch_count
Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/Makefile

@@ -62,6 +62,7 @@ i915-y += dvo_ch7017.o \
 	  intel_dsi_cmd.o \
 	  intel_dsi.o \
 	  intel_dsi_pll.o \
+	  intel_dsi_panel_vbt.o \
 	  intel_dvo.o \
 	  intel_hdmi.o \
 	  intel_i2c.o \

drivers/gpu/drm/i915/intel_dsi.c

@@ -35,6 +35,11 @@
 
 /* the sub-encoders aka panel drivers */
 static const struct intel_dsi_device intel_dsi_devices[] = {
+	{
+		.panel_id = MIPI_DSI_GENERIC_PANEL_ID,
+		.name = "vbt-generic-dsi-vid-mode-display",
+		.dev_ops = &vbt_generic_dsi_display_ops,
+	},
 };
 
 static void band_gap_reset(struct drm_i915_private *dev_priv)

drivers/gpu/drm/i915/intel_dsi.h

@@ -133,4 +133,6 @@ static inline struct intel_dsi *enc_to_intel_dsi(struct drm_encoder *encoder)
 extern void vlv_enable_dsi_pll(struct intel_encoder *encoder);
 extern void vlv_disable_dsi_pll(struct intel_encoder *encoder);
 
+extern struct intel_dsi_dev_ops vbt_generic_dsi_display_ops;
+
 #endif /* _INTEL_DSI_H */