Changes

gsmtap: Increase txqueue max_length from 64 to 1024

The default value may be too low for main loop iterations writing a lot
of output. Increase it to a saner value.

Change-Id: Ie737e1d060ea3ee48631604bbae1b8b84cf787b9
(cherry picked from commit 5edb7d54a8265ad6f44afdd0d07eda041f54ed98)