intel/compiler: Fill a compiler statistics struct

This commit is all annoying plumbing work which just adds support for a
new brw_compile_stats struct.  This struct provides a binary driver
readable form of the same statistics we dump out to stderr when we
INTEL_DEBUG is set with a shader stage.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>

src/intel/compiler/brw_fs.h

@@ -428,7 +428,8 @@ public:
    ~fs_generator();
 
    void enable_debug(const char *shader_name);
-   int generate_code(const cfg_t *cfg, int dispatch_width);
+   int generate_code(const cfg_t *cfg, int dispatch_width,
+                     struct brw_compile_stats *stats);
    const unsigned *get_assembly();
 
 private: