nir: Drop an unused program/hash_table.h include.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Timothy Arceri <timothy.arceri@collabora.com>

src/compiler/nir/nir_lower_samplers.c

@@ -25,7 +25,6 @@
 
 #include "nir.h"
 #include "nir_builder.h"
-#include "program/hash_table.h"
 #include "compiler/glsl/ir_uniform.h"
 
 #include "main/compiler.h"