os-helpers-tpm2: compute_pcr7: allow overriding efivars

When computing the digest of PCR7, it may be necessary to override the
input variables used, in order to predict the value on the next boot.
Allow these inputs to be overridden using function parameters.

Change-type: patch
Signed-off-by: Joseph Kogut <joseph@balena.io>

meta-balena-common/recipes-support/os-helpers/os-helpers/os-helpers-tpm2

@@ -51,15 +51,15 @@ EOF
 )
     for i in $inputs; do
         var="${efivars_path}/${i}"
-        extend=$(
-            case $i in
-                "SecureBoot-${EFI_GLOBAL_VARIABLE_GUID}") override="${1}" ;;
-                "PK-${EFI_GLOBAL_VARIABLE_GUID}") override="${2}" ;;
-                "KEK-${EFI_GLOBAL_VARIABLE_GUID}") override="${3}" ;;
-                "db-${EFI_IMAGE_SECURITY_DATABASE_GUID}") override="${4}" ;;
-                "dbx-${EFI_IMAGE_SECURITY_DATABASE_GUID}") override="${5}" ;;
-            esac
+        case $i in
+            "SecureBoot-${EFI_GLOBAL_VARIABLE_GUID}") override="${1}" ;;
+            "PK-${EFI_GLOBAL_VARIABLE_GUID}") override="${2}" ;;
+            "KEK-${EFI_GLOBAL_VARIABLE_GUID}") override="${3}" ;;
+            "db-${EFI_IMAGE_SECURITY_DATABASE_GUID}") override="${4}" ;;
+            "dbx-${EFI_IMAGE_SECURITY_DATABASE_GUID}") override="${5}" ;;
+        esac
 
+        extend=$(
             if [ -n "${override}" ]; then
                     echo "${override}" | _hexdecode | tcgtool "$var" | _sha256
             else