panfrost: Mark blit shaders as internal

Fixes spam of blit shader nir when NIR_PRINT=1 is set.

Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6870>
diff --git a/src/panfrost/lib/pan_blit.c b/src/panfrost/lib/pan_blit.c
index ff1da6f..55f335c 100644
--- a/src/panfrost/lib/pan_blit.c
+++ b/src/panfrost/lib/pan_blit.c
@@ -53,6 +53,8 @@
         nir_builder *b = &_b;
         nir_shader *shader = b->shader;
 
+        shader->info.internal = true;
+
         nir_variable *c_src = nir_variable_create(shader, nir_var_shader_in, glsl_vector_type(GLSL_TYPE_FLOAT, 2), "coord");
         nir_variable *c_out = nir_variable_create(shader, nir_var_shader_out, glsl_vector_type(
                                 GLSL_TYPE_FLOAT, is_colour ? 4 : 1), "out");