Update kernel "SubmittingPatches" link

Author: rca

CONTRIBUTING.md

@@ -29,7 +29,7 @@ The style of the repo follows that of the Linux kernel, in particular:
 * More details in the body
 * Match surrounding coding style (line wrapping, spaces, etc)
 
-More details in the [SubmittingPatches](https://www.kernel.org/doc/Documentation/SubmittingPatches) document included with the Linux kernel.  In particular the following sections:
+More details in the [SubmittingPatches](https://www.kernel.org/doc/Documentation/process/submitting-patches.rst) document included with the Linux kernel.  In particular the following sections:
 
 * `2) Describe your changes`
 * `3) Separate your changes`