scan code only detects public domain notice of file with also gpl notice

[pkunz]

This is the file http://review.coreboot.org/gitweb?p=coreboot.git;a=blob;f=payloads/bayou/lzma.c;h=a7a8717c6ac6eaa992d4e1ee42fe181ec8b1ebf0;hb=HEAD
The text is

Coreboot interface to memory-saving variant of LZMA decoder

(C)opyright 2006 Carl-Daniel Hailfinger
Released under the GNU GPL v2 or later

Parts of this file are based on C/7zip/Compress/LZMA_C/LzmaTest.c from the LZMA
SDK 4.42, which is written and distributed to public domain by Igor Pavlov.