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>