defconfig: sdm855: Enable GLINK PKT device driver

The GLINK PKT driver provides a pkt device interface for userspace
clients to send and receive messages to the remote procs in the system.

Change-Id: I9a14df138efc9c3774c1adcd0e46a1a84cfcb2cd
Signed-off-by: Chris Lew <clew@codeaurora.org>