Revert "hostap: Add currnet PHY rate to status"

This reverts commit ec0b9ccb.

This commit has two issues:

1. We already query signal poll just above, so, wastes time querying the
   infor from the firmware.
2. Doesn't handle modes, i.e., queries even for AP mode as well.

Signed-off-by: Chaitanya Tata <Chaitanya.Tata@nordicsemi.no>