docs: kernel-hacking: Remove inappropriate text

Remove inappropriate sexual (and ableist) text from the locking
documentation, aligning it with the kernel code-of-conduct. As the text
was unrelated to locking, this change streamlines the document and
improves readability.
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Link: https://lore.kernel.org/r/20210903151826.6300-1-alyssa@rosenzweig.ioSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/kernel-hacking/locking.rst

@@ -94,16 +94,10 @@ primitives, but I'll pretend they don't exist.
 Locking in the Linux Kernel
 ===========================
 
-If I could give you one piece of advice: never sleep with anyone crazier
-than yourself. But if I had to give you advice on locking: **keep it
-simple**.
+If I could give you one piece of advice on locking: **keep it simple**.
 
 Be reluctant to introduce new locks.
 
-Strangely enough, this last one is the exact reverse of my advice when
-you **have** slept with someone crazier than yourself. And you should
-think about getting a big dog.
-
 Two Main Types of Kernel Locks: Spinlocks and Mutexes
 -----------------------------------------------------