usb: Add support for rndis uplink aggregation

RNDIS protocol supports data aggregation on uplink and can help
reduce mips by reducing number of interrupts on device. Throughput
also improved by 20-30%. Aggregation is disabled by setting
aggregation packet size to 1. To help better UL throughput, set
as ul aggregation support to 3 rndis packets by default. It can be
configured via module parameter: rndis_ul_max_pkt_per_xfer.

Change-Id: I0b62a21a5c3ceb6b04933d0d6da33301dbafe493
Signed-off-by: Vamsi Krishna <vskrishn@codeaurora.org>
Signed-off-by: Xerox Lin <xerox_lin@htc.com>