net: rmnet_data: Add snapshot of rmnet_data driver

This is a snapshot of the rmnet_data driver taken as of msm-4.4.
commit 5da00923b1544ba ("rmnet_data: Changing format specifier to
%pK").

Additionally, fix some style issues reported by checkpatch.

CRs-Fixed: 1078373
Change-Id: Idb2df22e61803e04a01db64ea5e9d1e93ae92e09
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>