net: rmnet_data: Optimized GRO for single flow

Port single flow dynamic GRO changes into rmnet driver. This
feature uses configurable parameters that determine when GRO
should be flushed based on both timing and receive byte count.
Although the parameters are initially set, they dynamically
fluctuate based on incoming traffic.

CRs-Fixed: 1113125
Change-Id: I7469118d3108e0c9f71c4f50efd8ceebfb324a63
Signed-off-by: Conner Huff <chuff@codeaurora.org>