drm/i915: consider HAS_FLAT_CCS() in needs_ccs_pages

Just move the HAS_FLAT_CCS() check into needs_ccs_pages. This also then
fixes i915_ttm_memcpy_allowed() which was incorrectly reporting true on
DG1, even though it doesn't have small-BAR or flat-CCS.

References: https://gitlab.freedesktop.org/drm/intel/-/issues/6605
Fixes: efeb3caf ("drm/i915/ttm: disallow CPU fallback mode for ccs pages")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220905105329.41455-1-matthew.auld@intel.com

drivers/gpu/drm/i915/gem/i915_gem_object.c

@@ -723,6 +723,9 @@ bool i915_gem_object_needs_ccs_pages(struct drm_i915_gem_object *obj)
 	bool lmem_placement = false;
 	int i;
 
+	if (!HAS_FLAT_CCS(to_i915(obj->base.dev)))
+		return false;
+
 	for (i = 0; i < obj->mm.n_placements; i++) {
 		/* Compression is not allowed for the objects with smem placement */
 		if (obj->mm.placements[i]->type == INTEL_MEMORY_SYSTEM)

drivers/gpu/drm/i915/gem/i915_gem_ttm.c

@@ -297,7 +297,7 @@ static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object *bo,
 		i915_tt->is_shmem = true;
 	}
 
-	if (HAS_FLAT_CCS(i915) && i915_gem_object_needs_ccs_pages(obj))
+	if (i915_gem_object_needs_ccs_pages(obj))
 		ccs_pages = DIV_ROUND_UP(DIV_ROUND_UP(bo->base.size,
 						      NUM_BYTES_PER_CCS_BYTE),
 					 PAGE_SIZE);