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_block_device.c b/lib/efi_selftest/efi_selftest_block_device.c
index ad53dac..62b3e04 100644
--- a/lib/efi_selftest/efi_selftest_block_device.c
+++ b/lib/efi_selftest/efi_selftest_block_device.c
@@ -180,7 +180,7 @@
  *
  * @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)
@@ -240,7 +240,7 @@
 /*
  * Tear down unit test.
  *
- * @return:	EFI_ST_SUCCESS for success
+ * Return:	EFI_ST_SUCCESS for success
  */
 static int teardown(void)
 {
@@ -292,7 +292,7 @@
 /*
  * Execute unit test.
  *
- * @return:	EFI_ST_SUCCESS for success
+ * Return:	EFI_ST_SUCCESS for success
  */
 static int execute(void)
 {