net: rmnet_data: Handle buffer bloat for TCP scenarios

After commit 605ad7f1 ("tcp: refine TSO autosizing"), kernel
throttles uplink TCP data in case there is not sufficient amount
of socket buffer available due to delayed release of buffers
through TX completions in the physical net device.

Work around this by orphaning the socket buffer. This makes the
kernel assume that more packets can be sent in this scenario.
Out of band signaling and flow controlling at qdisc / HTB layer
should guarantee no issue for flow control.

Throughput difference for IPv4 TCP UL -

Before change : 143Mbps
After change  : 146Mbps

CRs-Fixed: 1088104
Change-Id: I251ed7938c29e08954d4c81d3041cb235a39d266
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>