softpipe: fix a warning due to an incorrect enum comparison

no change in behavior, because both are defined the same

Acked-by: Jose Fonseca <jfonseca@vmware.com>
diff --git a/src/gallium/drivers/softpipe/sp_image.c b/src/gallium/drivers/softpipe/sp_image.c
index a7c7328..f72c4e7 100644
--- a/src/gallium/drivers/softpipe/sp_image.c
+++ b/src/gallium/drivers/softpipe/sp_image.c
@@ -170,7 +170,7 @@
       *width = u_minify(spr->base.width0, level);
       *height = u_minify(spr->base.height0, level);
 
-      if (spr->base.target == TGSI_TEXTURE_3D)
+      if (spr->base.target == PIPE_TEXTURE_3D)
          *depth = u_minify(spr->base.depth0, level);
       else
          *depth = spr->base.array_size;