drivers: rmnet: shs: Reduce Max Backlog limit

Some small OOO packets were still seen in extreme cases.
Reducing the backlog limit threshold slightly.

Change-Id: I9ccd09445d521e94879bef5cba2041702086e83d
Acked-by: Raul Martinez <mraul@qti.qualcomm.com>
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>