P2P: Allow auto GO on DFS channels if driver supports this

P2P: Allow auto GO on DFS channels if driver supports this

If a DFS forced frequency is provided in 'p2p_group_add' and the driver
supports DFS offload, the frequency was rejected in
wpas_p2p_init_go_params(). However, it was accepted in
wpas_p2p_select_go_freq() and wpas_p2p_group_add(). To make the behavior
consistent, the DFS frequency is now accepted in
wpas_p2p_init_go_params() similar to the way done in
wpas_p2p_select_go_freq().

Redundant check in wpas_p2p_group_add() for DFS forced frequency is
removed.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>