broadcom/vc5: Clamp min lod to the last level.

Otherwise, the simulator would complain in tex-miplevel-selection that the
min/max clamp was out of order.  The actual HW seems to have clamped to
the max anyway.
diff --git a/src/gallium/drivers/vc5/vc5_emit.c b/src/gallium/drivers/vc5/vc5_emit.c
index 72b5d85..d535667 100644
--- a/src/gallium/drivers/vc5/vc5_emit.c
+++ b/src/gallium/drivers/vc5/vc5_emit.c
@@ -141,8 +141,9 @@
                  * TEXTURE_SHADER_STATE that ignores psview->min/max_lod to
                  * support txf properly.
                  */
-                .min_level_of_detail = (psview->u.tex.first_level +
-                                        MAX2(psampler->min_lod, 0)),
+                .min_level_of_detail = MIN2(psview->u.tex.first_level +
+                                            MAX2(psampler->min_lod, 0),
+                                            psview->u.tex.last_level),
                 .max_level_of_detail = MIN2(psview->u.tex.first_level +
                                             psampler->max_lod,
                                             psview->u.tex.last_level),