libc: Check for NULL pointers in free()
libc: Check for NULL pointers in free()

POSIX says that the free() function should simply do nothing if a NULL
pointer argument has been specified. So let's be a little bit more
compliant in our libc and add a NULL pointer check here, too.

Reviewed-by: Greg Kurz <cc878073a22fe20c2ded9f6f326476101ddf4b25@kaod.org>
Signed-off-by: Thomas Huth <9e65be74847981e55b2564b6266c57d86d3bac05@redhat.com>
Signed-off-by: Alexey Kardashevskiy <ac1fc56530d7d037e1ea666f130daca22d72f964@ozlabs.ru>

aik/SLOF,stefanberger/SLOF-tpm,stefanberger/SLOF-tpm,aik/SLOF,qemu/SLOF,aik/SLOF,stefanberger/SLOF-tpm,qemu/SLOF,qemu/SLOF