SubmittingPatches: add a reference to Andi's OLS paper

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>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>