nir: Fix #include guards in shader_enums.h.

This header was originally going to be called pipeline.h, but it got
renamed at the last minute.  Make the include guards match.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>

src/glsl/shader_enums.h

@@ -23,8 +23,8 @@
  * OTHER DEALINGS IN THE SOFTWARE.
  */
 
-#ifndef PIPELINE_H
-#define PIPELINE_H
+#ifndef SHADER_ENUMS_H
+#define SHADER_ENUMS_H
 
 /**
  * Bitflags for system values.
@@ -167,4 +167,4 @@ enum glsl_interp_qualifier
 };
 
 
-#endif /* PIPELINE_H */
+#endif /* SHADER_ENUMS_H */