[U-Boot] [PATCH 2/2] libavb: Fix build warnings after updating the lib

[Sam Protsenko]

After updating libavb to most recent version from AOSP/master, two new
warnings appear:

Warning #1:

    lib/libavb/avb_cmdline.c: In function 'avb_append_options':
    lib/libavb/avb_cmdline.c:365:15: warning: 'dm_verity_mode' may be
                                     used uninitialized in this function
                                     [-Wmaybe-uninitialized]
         new_ret = avb_replace(
                   ^~~~~~~~~~~~
             slot_data->cmdline, "$(ANDROID_VERITY_MODE)", dm_verity_mode);
             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    lib/libavb/avb_cmdline.c:374:8: warning: 'verity_mode' may be used
                                    uninitialized in this function
                                    [-Wmaybe-uninitialized]
       if (!cmdline_append_option(
            ^~~~~~~~~~~~~~~~~~~~~~
               slot_data, "androidboot.veritymode", verity_mode)) {
               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Warning #2:

    lib/libavb/avb_slot_verify.c: In function 'avb_slot_verify':
    lib/libavb/avb_slot_verify.c:1349:23: warning: 'ret' may be used
                                          uninitialized in this function
                                          [-Wmaybe-uninitialized]
       AvbSlotVerifyResult ret;
                           ^~~

Fix those by providing default return values to affected functions.

Signed-off-by: Sam Protsenko <semen.protsenko at linaro.org>
---
 lib/libavb/avb_cmdline.c     | 3 ++-
 lib/libavb/avb_slot_verify.c | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/libavb/avb_cmdline.c b/lib/libavb/avb_cmdline.c
index cb5b98e423..684c512bb9 100644
--- a/lib/libavb/avb_cmdline.c
+++ b/lib/libavb/avb_cmdline.c
@@ -357,7 +357,8 @@ AvbSlotVerifyResult avb_append_options(
         // Should never get here because MANAGED_RESTART_AND_EIO is
         // remapped by avb_manage_hashtree_error_mode().
         avb_assert_not_reached();
-        break;
+        ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT;
+        goto out;
       default:
         ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT;
         goto out;
diff --git a/lib/libavb/avb_slot_verify.c b/lib/libavb/avb_slot_verify.c
index 5d400b38aa..c0defdf9c9 100644
--- a/lib/libavb/avb_slot_verify.c
+++ b/lib/libavb/avb_slot_verify.c
@@ -1346,7 +1346,7 @@ AvbSlotVerifyResult avb_slot_verify(AvbOps* ops,
                                     AvbSlotVerifyFlags flags,
                                     AvbHashtreeErrorMode hashtree_error_mode,
                                     AvbSlotVerifyData** out_data) {
-  AvbSlotVerifyResult ret;
+  AvbSlotVerifyResult ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT;
   AvbSlotVerifyData* slot_data = NULL;
   AvbAlgorithmType algorithm_type = AVB_ALGORITHM_TYPE_NONE;
   bool using_boot_for_vbmeta = false;
-- 
2.23.0.rc1