efi_loader: correct function comment style

Replace @return and @param.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/lib/efi_selftest/efi_selftest_events.c b/lib/efi_selftest/efi_selftest_events.c
index 1077cbd..9007153 100644
--- a/lib/efi_selftest/efi_selftest_events.c
+++ b/lib/efi_selftest/efi_selftest_events.c
@@ -39,7 +39,7 @@
  *
  * @handle:	handle of the loaded image
  * @systable:	system table
- * @return:	EFI_ST_SUCCESS for success
+ * Return:	EFI_ST_SUCCESS for success
  */
 static int setup(const efi_handle_t handle,
 		 const struct efi_system_table *systable)
@@ -69,7 +69,7 @@
  *
  * Close the events created in setup.
  *
- * @return:	EFI_ST_SUCCESS for success
+ * Return:	EFI_ST_SUCCESS for success
  */
 static int teardown(void)
 {
@@ -103,7 +103,7 @@
  * Run a 100 ms single shot timer and check that it is called once
  * while waiting for 100 ms periodic timer for two periods.
  *
- * @return:	EFI_ST_SUCCESS for success
+ * Return:	EFI_ST_SUCCESS for success
  */
 static int execute(void)
 {