Add a reference to paper to SubmittingPatches

Add a reference to paper to SubmittingPatches

For this year's OLS I wrote a paper on successfull strategies
to submit difficult kernel patches. Add a reference to it to
SubmittingPatches.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>