pkg/intel/metadara: fix bgheader parser, add multiversion detection (#397)

* parse entire struct
* Switch to variable detection range

Signed-off-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>

Author: zaolin

pkg/intel/metadata/common/bgheader/bgheader.go

@@ -40,20 +40,15 @@ func (bgv BootGuardVersion) String() string {
 
 func DetectBGV(r io.Reader) (BootGuardVersion, error) {
 	var s structInfo
-	err := binary.Read(r, binaryOrder, s.ID[:])
+	err := binary.Read(r, binaryOrder, &s)
 	if err != nil {
 		return 0, fmt.Errorf("unable to read field 'ID': %w", err)
 	}
-	err = binary.Read(r, binaryOrder, s.Version)
-	if err != nil {
-		return 0, fmt.Errorf("unable to read field 'Version': %w", err)
-	}
-	switch s.Version {
-	case 0x10:
-		return Version10, nil
-	case 0x20:
+	if s.Version >= 0x20 {
 		return Version20, nil
-	default:
+	} else if (s.Version < 0x20) && (s.Version >= 0x10) {
+		return Version10, nil
+	} else {
 		return 0, fmt.Errorf("couldn't detect version")
 	}
 }