Bluetooth: Check for SCO type before setting retransmission effort

SCO connection cannot be setup to devices that do not support retransmission.
Patch based on http://permalink.gmane.org/gmane.linux.bluez.kernel/7779

 and
adapted for this kernel version.

Code changed to check SCO/eSCO type before setting retransmission effort
and max. latency. The purpose of the patch is to support older devices not
capable of eSCO.

Tested on Blackberry 655+ headset which does not support retransmission.
Credits go to Alexander Sommerhuber.

Signed-off-by: Bernhard Thaler <bernhard.thaler@r-it.at>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>