Bluetooth: L2CAP_BR: Set flags in CFG RSP

The flags of L2CAP_CONFIGURATION_REQ are set.
But in L2CAP_CONFIGURATION_RSP, all bits of
flags are cleared.

When used in the L2CAP_CONFIGURATION_RSP
packet, the continuation flag shall be set
to one if the flag is set to one in the
Request.

Copy flags from Request to Response if it
is a successful result.

Signed-off-by: Lyle Zhu <lyle.zhu@nxp.com>