iwlwifi: mvm: remove P2P_DEVICE support

Unfortunately, advertising P2P_DEVICE support was a little
premature, a number of issues came up in testing and have
been fixed for 3.10. Rather than try to backport all the
different fixes, disable P2P_DEVICE support in the drivers
using it. For iwlmvm that implies disabling P2P completely
as it can't support P2P operation w/o P2P Device.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>