buildroot

package/ola: disable fatal warnings for host variant

By default the build system of OLA passes '-Werror' to GCC. The aborts
compilation with GCC 6:

'''
error: ‘template<class> class std::auto_ptr’ is deprecated
[-Werror=deprecated-declarations]
'''

The target variant already passes the option "-disable-fatal-warnings"
to the build system to disable '-Werror'. Do it for the host variant to
to fix build with host GCC 6.

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>