util: Move the open-addressing linear-probing hash_table to src/util.

This hash table is used in core Mesa, the GLSL compiler, and the i965
driver, which makes it a good candidate for the new src/util module.

It's much faster than program/hash_table.[ch] (see commit 6991c2922f
for data), and José's u_hash_table.c has a comment saying Gallium should
probably consider switching to a linear probing hash table at some point.
So this seems like the best candidate for a shared data structure.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>

v2 (Jason Ekstrand): Pick up another hash_table use and patch up scons

Signed-off-by: Jason Ekstrand <jason.ekstrand@intel.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/glsl/link_uniform_blocks.cpp

@@ -26,7 +26,7 @@
 #include "linker.h"
 #include "ir_uniform.h"
 #include "link_uniform_block_active_visitor.h"
-#include "main/hash_table.h"
+#include "util/hash_table.h"
 #include "program.h"
 
 namespace {