libjpeg-turbo: Fix of 2 CVEs

CVE-2020-13790: fix heap buffer over-read in rdppm.c with a crafted binary PPM/PGM file with upstream 6709e4a0 and 1e81b0c3: range-check text PPM/PGM samples and 16-bit binary words against maxval; also CVE-2016-3616, CVE-2018-11213, CVE-2018-11214 - CVE-2020-17541: fix stack buffer overflow in...