glsl: Just access the ir_expression_operation strings table directly

The operator_string functions gave us some protection against a
malformed table.  Now that the table is generated from the same data
that generates the enum, this is not a concern.  Just cut out the middle
man.

   text	   data	    bss	    dec	    hex	filename
7531892	 273992	  28584	7834468	 778b64	i965_dri-64bit-before.so
7531828	 273992	  28584	7834404	 778b24	i965_dri-64bit-after.so

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>

src/compiler/glsl/ir_expression_operation.py

@@ -365,7 +365,7 @@ ${item}
 };""")
 
    strings_template = mako.template.Template(copyright + """
-static const char *const operator_strs[] = {
+const char *const ir_expression_operation_strings[] = {
 % for item in values:
 %  if not isinstance(item, str):
    "${item[2] if item[2] is not None else item[0]}",