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/cluster/cluster_bootstrap.go b/metropolis/node/core/cluster/cluster_bootstrap.go
index 690af00..312874d 100644
--- a/metropolis/node/core/cluster/cluster_bootstrap.go
+++ b/metropolis/node/core/cluster/cluster_bootstrap.go
@@ -90,13 +90,13 @@
 	if err != nil {
 		return fmt.Errorf("could not generate node keypair: %w", err)
 	}
-	supervisor.Logger(ctx).Infof("Bootstrapping: node public key: %s", hex.EncodeToString([]byte(pub)))
+	supervisor.Logger(ctx).Infof("Bootstrapping: node public key: %s", hex.EncodeToString(pub))
 
 	jpub, jpriv, err := ed25519.GenerateKey(rand.Reader)
 	if err != nil {
 		return fmt.Errorf("could not generate join keypair: %w", err)
 	}
-	supervisor.Logger(ctx).Infof("Bootstrapping: node public join key: %s", hex.EncodeToString([]byte(jpub)))
+	supervisor.Logger(ctx).Infof("Bootstrapping: node public join key: %s", hex.EncodeToString(jpub))
 
 	directory := &cpb.ClusterDirectory{
 		Nodes: []*cpb.ClusterDirectory_Node{
diff --git a/metropolis/node/core/cluster/cluster_register.go b/metropolis/node/core/cluster/cluster_register.go
index 61cea56..1bda9a9 100644
--- a/metropolis/node/core/cluster/cluster_register.go
+++ b/metropolis/node/core/cluster/cluster_register.go
@@ -120,7 +120,7 @@
 	if err != nil {
 		return fmt.Errorf("could not generate join keypair: %w", err)
 	}
-	supervisor.Logger(ctx).Infof("Registering: join public key: %s", hex.EncodeToString([]byte(jpub)))
+	supervisor.Logger(ctx).Infof("Registering: join public key: %s", hex.EncodeToString(jpub))
 
 	// Register this node.
 	//
diff --git a/metropolis/node/core/network/main.go b/metropolis/node/core/network/main.go
index 7426ee4..b40bc98 100644
--- a/metropolis/node/core/network/main.go
+++ b/metropolis/node/core/network/main.go
@@ -130,7 +130,7 @@
 // nftables)
 func nfifname(n string) []byte {
 	b := make([]byte, 16)
-	copy(b, []byte(n+"\x00"))
+	copy(b, n+"\x00")
 	return b
 }
 
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 {