msm: ipa: tx interrupt mitigation changes

Original scheme queued a work item for every TX interrupt.
This led to high CPU utilization and also impacted
throughput. This change applies the existing RX interruption
mitigation scheme to the TX path also. The polling sleep
interval values are tuned for TX path. Also, this scheme
applies only to data packets and not immediate commands.

Change-Id: Id87da0c2665aa6af56a0fcd1bda329bd15bf9f0c
Signed-off-by: Ravi Gummadidala <rgummadi@codeaurora.org>