Documentation/process: submitting-patches: fix typo in "were do"

Fixes a typo in submitting-patches.rst:
"were do" -> "where do"

Signed-off-by: Yash Suthar <[e-mail]>
Acked-by: Randy Dunlap <[e-mail]>
Signed-off-by: Jonathan Corbet <[e-mail]>
Message-ID: <[e-mail]>

Documentation/process/submitting-patches.rst

···
 As is frequently quoted on the mailing list::
 
   A: http://en.wikipedia.org/wiki/Top_post
-  Q: Were do I find info about this thing called top-posting?
+  Q: Where do I find info about this thing called top-posting?
   A: Because it messes up the order in which people normally read text.
   Q: Why is top-posting such a bad thing?
   A: Top-posting.