drm/radeon/r600_cs: remove r600_cs_legacy_get_tiling_conf() declaration

r600_cs_legacy_get_tiling_conf() has been removed since
commit 8333f607 ("drm/radeon: remove UMS support"),
so remove it.
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220913024847.552254-3-cuigaosheng1@huawei.com

drivers/gpu/drm/radeon/r600_cs.c

@@ -34,8 +34,6 @@
 #include "r600_reg_safe.h"
 
 static int r600_nomm;
-extern void r600_cs_legacy_get_tiling_conf(struct drm_device *dev, u32 *npipes, u32 *nbanks, u32 *group_size);
-
 
 struct r600_cs_track {
 	/* configuration we mirror so that we use same code btw kms/ums */