drm/i915/dram: hide the dram structs better

Finish the job started in d28ae3b28187 ("drm/i915: split out
intel_dram.[ch] from i915_drv.c") by moving struct dram_dimm_info and
dram_channel_info inside intel_dram.c, the only user of the structs.

Reviewed-by: Ville Syrjälä <[e-mail]>
Signed-off-by: Jani Nikula <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/i915/i915_drv.h

···
 	 */
 };
 
-struct dram_dimm_info {
-	u8 size, width, ranks;
-};
-
-struct dram_channel_info {
-	struct dram_dimm_info dimm_l, dimm_s;
-	u8 ranks;
-	bool is_16gb_dimm;
-};
-
 static inline struct drm_i915_private *to_i915(const struct drm_device *dev)
 {
 	return container_of(dev, struct drm_i915_private, drm);

drivers/gpu/drm/i915/intel_dram.c

···
 #include "i915_drv.h"
 #include "intel_dram.h"
 
+struct dram_dimm_info {
+	u8 size, width, ranks;
+};
+
+struct dram_channel_info {
+	struct dram_dimm_info dimm_l, dimm_s;
+	u8 ranks;
+	bool is_16gb_dimm;
+};
+
 #define DRAM_TYPE_STR(type) [INTEL_DRAM_ ## type] = #type
 
 static const char *intel_dram_type_str(enum intel_dram_type type)