drm/i915: move mipi_mmio_base to display.dsi

Move display DSI related members under drm_i915_private display
sub-struct.

Prefer adding anonymous sub-structs even for single members that aren't
our own structs.

Abstract mmio base member access in register definitions in a macro.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/dc7c5a871fe558a809ea943eca5c71dfff1740a8.1661779055.git.jani.nikula@intel.com

drivers/gpu/drm/i915/display/intel_display_core.h

@@ -249,6 +249,11 @@ struct intel_display {
 		unsigned int max_cdclk_freq;
 	} cdclk;
 
+	struct {
+		/* VLV/CHV/BXT/GLK DSI MMIO register base address */
+		u32 mmio_base;
+	} dsi;
+
 	struct {
 		/* list of fbdev register on this device */
 		struct intel_fbdev *fbdev;

drivers/gpu/drm/i915/display/vlv_dsi.c

@@ -1872,9 +1872,9 @@ void vlv_dsi_init(struct drm_i915_private *dev_priv)
 		return;
 
 	if (IS_GEMINILAKE(dev_priv) || IS_BROXTON(dev_priv))
-		dev_priv->mipi_mmio_base = BXT_MIPI_BASE;
+		dev_priv->display.dsi.mmio_base = BXT_MIPI_BASE;
 	else
-		dev_priv->mipi_mmio_base = VLV_MIPI_BASE;
+		dev_priv->display.dsi.mmio_base = VLV_MIPI_BASE;
 
 	intel_dsi = kzalloc(sizeof(*intel_dsi), GFP_KERNEL);
 	if (!intel_dsi)

drivers/gpu/drm/i915/i915_drv.h

@@ -299,9 +299,6 @@ struct drm_i915_private {
 
 	struct intel_wopcm wopcm;
 
-	/* MMIO base address for MIPI regs */
-	u32 mipi_mmio_base;
-
 	struct pci_dev *bridge_dev;
 
 	struct rb_root uabi_engines;