Bluetooth: Use GFP_KERNEL in sco_conn_add

This patch changes the memory allocation flags in the sco_conn_add
function, replacing the type to GFP_KERNEL. This function is executed
in process context and it is not called inside an atomic section.

Signed-off-by: Claudio Takahasi <claudio.takahasi@openbossa.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>