carl9170: remove P2P_GO support

This patch follows up on a bug-report by Frank Schäfer that
discovered P2P GO wasn't working with wpa_supplicant.
This patch removes part of the broken P2P GO support but
keeps the vif switchover code in place.

Cc: <stable@vger.kernel.org>
Link: <https://lkml.kernel.org/r/3a9d86b6-744f-e670-8792-9167257edef8@googlemail.com>
Reported-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200425092811.9494-1-chunkeey@gmail.com