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_tpl.c b/lib/efi_selftest/efi_selftest_tpl.c
index 0c0e412..f4e4672 100644
--- a/lib/efi_selftest/efi_selftest_tpl.c
+++ b/lib/efi_selftest/efi_selftest_tpl.c
@@ -37,7 +37,7 @@
  *
  * @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)
@@ -68,7 +68,7 @@
  *
  * Close the events created in setup.
  *
- * @return:	EFI_ST_SUCCESS for success
+ * Return:	EFI_ST_SUCCESS for success
  */
 static int teardown(void)
 {
@@ -106,7 +106,7 @@
  * Lower the TPL level and check that the queued notification
  * function is called.
  *
- * @return:	EFI_ST_SUCCESS for success
+ * Return:	EFI_ST_SUCCESS for success
  */
 static int execute(void)
 {