treewide: remove unnecessary types and conversions

Change-Id: Ifcaa9ceeec243b3646c9b6e0a6fad7ef2db8fd90
Reviewed-on: https://review.monogon.dev/c/monogon/+/2954
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
Tested-by: Jenkins CI
diff --git a/metropolis/node/core/update/update.go b/metropolis/node/core/update/update.go
index ce0d021..ad4ad43 100644
--- a/metropolis/node/core/update/update.go
+++ b/metropolis/node/core/update/update.go
@@ -409,7 +409,7 @@
 	if err != nil {
 		return fmt.Errorf("failed to list EFI variables: %w", err)
 	}
-	var validBootEntryIdx int = -1
+	var validBootEntryIdx = -1
 	for _, varName := range varNames {
 		m := bootVarRegexp.FindStringSubmatch(varName)
 		if m == nil {