wavpack: add upstream security fixes

wavpack: add upstream security fixes

Fixes the following security issues:

CVE-2018-6767: A stack-based buffer over-read in the ParseRiffHeaderConfig
function of cli/riff.c file of WavPack 5.1.0 allows a remote attacker to
cause a denial-of-service attack or possibly have unspecified other impact
via a maliciously crafted RF64 file.

CVE-2018-7253: The ParseDsdiffHeaderConfig function of the cli/dsdiff.c file
of WavPack 5.1.0 allows a remote attacker to cause a denial-of-service
(heap-based buffer over-read) or possibly overwrite the heap via a
maliciously crafted DSDIFF file.

CVE-2018-7254: The ParseCaffHeaderConfig function of the cli/caff.c file of
WavPack 5.1.0 allows a remote attacker to cause a denial-of-service (global
buffer over-read), or possibly trigger a buffer overflow or incorrect memory
allocation, via a maliciously crafted CAF file.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>