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_rtc.c b/lib/efi_selftest/efi_selftest_rtc.c
index 6f7035d..e9e47e9 100644
--- a/lib/efi_selftest/efi_selftest_rtc.c
+++ b/lib/efi_selftest/efi_selftest_rtc.c
@@ -19,7 +19,7 @@
  *
  * @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)
@@ -35,7 +35,7 @@
  * Set a new value and read it back.
  * Set the real time clock back the current time.
  *
- * @return:	EFI_ST_SUCCESS for success
+ * Return:	EFI_ST_SUCCESS for success
  */
 static int execute(void)
 {