intel/common: consistently use ifndef guards over pragma once

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Acked-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Acked-by: Vedran Miletić <vedran@miletic.net>
Acked-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Reviewed-by: Edward O'Callaghan <funfunctor@folklore1984.net>

src/intel/common/gen_debug.h

@@ -22,7 +22,9 @@
  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
-#pragma once
+
+#ifndef GEN_DEBUG_H
+#define GEN_DEBUG_H
 
 #include <stdint.h>
 #include "compiler/shader_enums.h"
@@ -133,3 +135,5 @@ extern void brw_process_intel_debug_variable(void);
 #ifdef __cplusplus
 }
 #endif
+
+#endif /* GEN_DEBUG_H */