drm/tests: Fix drm_test_fb_xrgb8888_to_xrgb2101010() on big-endian

Fix failures on big-endian architectures on tests cases
single_pixel_source_buffer, single_pixel_clip_rectangle,
well_known_colors and destination_pitch.

Fixes: 15bda1f ("drm/tests: Add calls to drm_fb_blit() on supported format conversion tests")
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://lore.kernel.org/r/20250630090054.353246-2-jose.exposito89@gmail.com

Author: JoseExposito

drivers/gpu/drm/tests/drm_format_helper_test.c

@@ -1040,6 +1040,7 @@ static void drm_test_fb_xrgb8888_to_xrgb2101010(struct kunit *test)
 	memset(buf, 0, dst_size);
 
 	drm_fb_xrgb8888_to_xrgb2101010(&dst, dst_pitch, &src, &fb, &params->clip, &fmtcnv_state);
+	buf = le32buf_to_cpu(test, (__force const __le32 *)buf, dst_size / sizeof(u32));
 	KUNIT_EXPECT_MEMEQ(test, buf, result->expected, dst_size);
 }