drm/i915/display: include gem/i915_gem_stolen.h where needed

Include what you use. We need to move the compat i915_gem_stolen.h under
gem subdir. With this, we can drop the include from xe compat
i915_drv.h.
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/6ac3480a8689fda5aaf4007cb604e06e939a03f7.1717004739.git.jani.nikula@intel.com

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

@@ -43,6 +43,7 @@
 #include <drm/drm_blend.h>
 #include <drm/drm_fourcc.h>
 
+#include "gem/i915_gem_stolen.h"
 #include "i915_drv.h"
 #include "i915_reg.h"
 #include "i915_utils.h"

drivers/gpu/drm/xe/compat-i915-headers/i915_drv.h

@@ -19,7 +19,6 @@
 #include "xe_bo.h"
 #include "xe_pm.h"
 #include "xe_step.h"
-#include "i915_gem_stolen.h"
 #include "i915_gpu_error.h"
 #include "i915_reg_defs.h"
 #include "i915_utils.h"