tf-a-tools: Add bbappend to fix native build on host without openssl-devel

The Makefile has some assumptions which result in a dependency on
openssl-devel on the host. The exact same problem was already fixed in
the meta-arm layer so we are simply going with the same sed solution and
add the native dependency on openssl.

https://git.yoctoproject.org/cgit/cgit.cgi/meta-arm/tree/meta-arm/recipes-bsp/trusted-firmware-a/trusted-firmware-a.inc#n162



Signed-off-by: Stefan Schmidt <stefan.schmidt@huawei.com>