Bluetooth: Host: Fix auto-connect/sync establishment on Coded PHY

As documented in bt_le_scan_update(), the host may start scanning
automatically for various reasons.

Until now scanning was only done on 1M PHY, making it impossible
to use auto-connect/sync establishment if the advertiser was using
Coded PHY as its primary PHY.

Auto-connection would never work. Sync establishment would work if
the scanner was started by the application.

This commit fixes this by instructing the controller to scan on
both 1M and Coded PHY if the controller supports Coded PHY.
The application may see increased power consumption as a result
of this change as the controller may now spend 2*scan_window
listening for advertising packets.

Signed-off-by: Rubin Gerritsen <rubin.gerritsen@nordicsemi.no>