net: qualcomm: rmnet: Allow uplink aggregation configuration

Allow userspace to configure the uplink aggregation parameters through
RTM_NEWLINK messages. Userspace can set the maximum byte count, packet
count, and time limit that the RmNet driver will use when aggregating
egress packets.

Change-Id: I941800b11b8181e661d131348b65668e72539a7e
Signed-off-by: Sean Tranchetti <stranche@codeaurora.org>