drm/i915/selftests: skip the mman tests for stolen

It's not supported, and just skips later anyway. With small-BAR things
get more complicated since all of stolen is likely not even CPU
accessible, hence not passing I915_BO_ALLOC_GPU_ONLY just results in the
object create failing.
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Kenneth Graunke <kenneth@whitecape.org>
Cc: Akeem G Abodunrin <akeem.g.abodunrin@intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220629174350.384910-9-matthew.auld@intel.com

drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c

@@ -979,6 +979,9 @@ static int igt_mmap(void *arg)
 		};
 		int i;
 
+		if (mr->private)
+			continue;
+
 		for (i = 0; i < ARRAY_SIZE(sizes); i++) {
 			struct drm_i915_gem_object *obj;
 			int err;
@@ -1435,6 +1438,9 @@ static int igt_mmap_access(void *arg)
 		struct drm_i915_gem_object *obj;
 		int err;
 
+		if (mr->private)
+			continue;
+
 		obj = __i915_gem_object_create_user(i915, PAGE_SIZE, &mr, 1);
 		if (obj == ERR_PTR(-ENODEV))
 			continue;
@@ -1580,6 +1586,9 @@ static int igt_mmap_gpu(void *arg)
 		struct drm_i915_gem_object *obj;
 		int err;
 
+		if (mr->private)
+			continue;
+
 		obj = __i915_gem_object_create_user(i915, PAGE_SIZE, &mr, 1);
 		if (obj == ERR_PTR(-ENODEV))
 			continue;
@@ -1727,6 +1736,9 @@ static int igt_mmap_revoke(void *arg)
 		struct drm_i915_gem_object *obj;
 		int err;
 
+		if (mr->private)
+			continue;
+
 		obj = __i915_gem_object_create_user(i915, PAGE_SIZE, &mr, 1);
 		if (obj == ERR_PTR(-ENODEV))
 			continue;