commit 205e2210 upstream.

NICs supported by iwldvm don't handle well TX AMPDU.
Disable it by default, still leave the possibility to
the user to force enable it with a debug parameter.

NICs supported by iwlmvm don't suffer from the same issue,
leave TX AMPDU enabled by default for these.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>