Fix Doxygen headers for MPS files

Signed-off-by: Hanno Becker <hanno.becker@arm.com>
diff --git a/library/mps_error.h b/library/mps_error.h
index c11a01f..f78d9a0 100644
--- a/library/mps_error.h
+++ b/library/mps_error.h
@@ -18,7 +18,7 @@
  */
 
 /**
- * \file error.h
+ * \file mps_error.h
  *
  * \brief Error codes used by MPS
  */