iot: change the copy stages

Split this into two separate copystages so that we are not overriding
types.

internal/osbuild/ostree_input.go

@@ -5,7 +5,7 @@ type OSTreeInput struct {
 	inputCommon
 }
 
-func (OSTreeInput) isInput() {}
+func (OSTreeInput) isStageInputs() {}
 
 func NewOSTreeInput() *OSTreeInput {
 	input := new(OSTreeInput)
@@ -20,8 +20,6 @@ type OSTreeCheckoutInput struct {
 	References OSTreeCheckoutReferences `json:"references"`
 }
 
-func (OSTreeCheckoutInput) isInput() {}
-
 type OSTreeCheckoutReferences []string
 
 func (OSTreeCheckoutReferences) isReferences() {}
@@ -40,3 +38,7 @@ func NewOSTreeCheckoutInput(origin, name string) *OSTreeCheckoutInput {
 	input.References = inputRefs
 	return input
 }
+
+type OSTreeCheckoutInputs map[string]OSTreeCheckoutInput
+
+func (c OSTreeCheckoutInputs) isStageInputs() {}

internal/osbuild/tree_input.go

@@ -19,7 +19,7 @@ func NewTreeInput(reference string) *TreeInput {
 	return input
 }
 
-type PipelineTreeInputs map[string]Input
+type PipelineTreeInputs map[string]TreeInput
 
 func NewPipelineTreeInputs(name, pipeline string) *PipelineTreeInputs {
 	return &PipelineTreeInputs{