util/spd_tools: Add 'Generated by' string to part_id_gen output files

Add a 'Generated by' string to the generated Makefile.inc and
dram_id.generated.txt, showing the command used to generate the files.

BUG=b:191776301
TEST=Run part_id_gen, check that the generated files contain the string

Signed-off-by: Reka Norman <rekanorman@google.com>
Change-Id: Ic9a7826212a732288f36f111b7bc20365a1f702d
Reviewed-on: https://review.coreboot.org/c/coreboot/+/57692
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Maxim Polyakov <max.senia.poliak@gmail.com>
Reviewed-by: Furquan Shaikh <furquan@google.com>

util/spd_tools/src/part_id_gen/part_id_gen.go

@@ -244,6 +244,13 @@ type partIds struct {
 	memParts    string
 }
 
+func getFileHeader() string {
+    return `# SPDX-License-Identifier: GPL-2.0-or-later
+# This is an auto-generated file. Do not edit!!
+# Generated by:
+` + fmt.Sprintf("# %s\n\n", strings.Join(os.Args[0:], " "))
+}
+
 /*
  * For each part used by the variant, check if the SPD (as per the manifest) already has an ID
  * assigned to it. If yes, then add the part name to the list of memory parts supported by the
@@ -339,22 +346,19 @@ func genPartIdInfo(parts []usedPart, partToSPDMap map[string]string, SPDToIndexM
 	}
 
 	fmt.Printf("%s", s)
+
+	s = getFileHeader() + s
 	err := ioutil.WriteFile(filepath.Join(makefileDirName, DRAMIdFileName), []byte(s), 0644)
 
 	return partIdList, err
 }
 
-var generatedCodeLicense string = "## SPDX-License-Identifier: GPL-2.0-or-later"
-var autoGeneratedInfo string = "## This is an auto-generated file. Do not edit!!"
-
 /*
  * This function generates Makefile.inc under the variant directory path and adds assigned SPDs
  * to SPD_SOURCES.
  */
 func genMakefile(partIdList []partIds, makefileDirName string, SPDDir string) error {
-	var s string
-
-	s += fmt.Sprintf("%s\n%s\n\n", generatedCodeLicense, autoGeneratedInfo)
+	s := getFileHeader()
 	s += fmt.Sprintf("SPD_SOURCES =\n")
 
 	for i := 0; i < len(partIdList); i++ {