cmake: Use find_program if find_host_program is not available
CMake does not define the `find_host_program` command we've
been using in the cross-compiling code path. It was
provided by a widely used Android toolchain file. For
compatibility, continue to use `find_host_program` if
available, but otherwise use just `find_program`.
Signed-off-by: Maxime Roussin-Bélanger <maxime.roussinbelanger@gmail.com> Signed-off-by: Ross Burton <ross.burton@intel.com>
