arm: total_compute: Minor improvement for boot arguments

Tell the AVB command that is loading from MMC.

Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Signed-off-by: Leo Yan <leo.yan@arm.com>
diff --git a/board/armltd/total_compute/total_compute.env b/board/armltd/total_compute/total_compute.env
index 8975a86..9dd5081 100644
--- a/board/armltd/total_compute/total_compute.env
+++ b/board/armltd/total_compute/total_compute.env
@@ -7,7 +7,7 @@
     if part number mmc 0 vbmeta is_avb; then
         echo 'MMC with vbmeta partition detected.';
         echo 'Starting Android Verified boot...';
-        avb init 0;
+        avb init mmc 0;
         if avb verify; then
             set bootargs $bootargs $avb_bootargs;
             part start mmc 0 boot boot_start;