P2P: Add VHT parameter to P2P operations

P2P: Add VHT parameter to P2P operations

Add the option to ask for VHT operation similarly to the way ht40 is
configured - either by adding 'vht' param to the relevant p2p_*
commands or by configuring p2p_go_vht=1 in the configuration file.

This patch only adds the configuration option (e.g., via control
interface). The actual handling of the VHT parameter (asking the driver
to use VHT, etc.) will be done by the following patch.

Signed-hostap: Eliad Peller <eliadx.peller@intel.com>