Join iwl3945-firmware and iwl4965-firmware into iwlegacy-firmware
    
    There is no reason to keep those two small firmware packages separated,
    since nowadays a single kernel module uses them (iwlegacy). This can
    be seen also on the old subpackage descriptions mentioning the old
    modules that don't exist anymore.
    
    v2: Add provides to the obsoleted packages as suggested by Josh Boyer
    
    Signed-off-by: Herton R. Krzesinski <herton@redhat.com>