doc: re-add CodingStyle and SubmittingPatches

Those files got moved to Documentation/process, but as they're very
well known files, add pointers to their new locations.

PS.: I opted to not merge this patch with the previous one
in order to make the diff of the previous one more consistent,
as it will show only renames.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/Documentation/SubmittingPatches b/Documentation/SubmittingPatches
new file mode 100644
index 0000000..8145570
--- /dev/null
+++ b/Documentation/SubmittingPatches
@@ -0,0 +1 @@
+This file has moved to process/submitting-patches.rst