P2P: Fall back to no VHT when starting AP/P2P GO

P2P: Fall back to no VHT when starting AP/P2P GO

In cases where the bandwidth is not set when starting an AP/P2P GO,
the code tries to use 160 MHz or 80 MHz channels. As a result, the
AP/P2P GO configuration is set to use these channel widths even if
they are not available, which may results in failing to start the
AP/P2P GO.

Fix this by changing the AP/P2P GO configuration not to use VHT channels
when they are not available. In this case the AP/P2P GO will use a 40
MHz channel, if available, or a 20 MHz channel, if this is the maximum
available width.

Signed-off-by: Avraham Stern <avraham.stern@intel.com>