lshal: use pragma once

For simplicity when adding new files.

Bug: N/A
Test: N/A
Change-Id: Ia66e5da5ff680b9287c4431799a935b58de02307
diff --git a/cmds/lshal/NullableOStream.h b/cmds/lshal/NullableOStream.h
index 737d3a2..7cffcf8 100644
--- a/cmds/lshal/NullableOStream.h
+++ b/cmds/lshal/NullableOStream.h
@@ -14,8 +14,7 @@
  * limitations under the License.
  */
 
-#ifndef FRAMEWORK_NATIVE_CMDS_LSHAL_NULLABLE_O_STREAM_H_
-#define FRAMEWORK_NATIVE_CMDS_LSHAL_NULLABLE_O_STREAM_H_
+#pragma once
 
 #include <iostream>
 
@@ -69,5 +68,3 @@
 
 }  // namespace lshal
 }  // namespace android
-
-#endif  // FRAMEWORK_NATIVE_CMDS_LSHAL_NULLABLE_O_STREAM_H_