mwifiex: Fix copy-paste mistake when creating virtual interface

The BSS priority here for a new P2P_CLIENT device was accidentally set
to an enum that's certainly not meant for this. Since
MWIFIEX_BSS_ROLE_STA is 0 anyway, we can just set the bss_priority to 0
instead here.

Signed-off-by: Jonas Dreßler <verdre@v0yd.nl>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210914195909.36035-10-verdre@v0yd.nl