[PATCH] Remove references to obsolete kernel config option DEBUG_RWSEMS

Remove the few references to the obsolete kernel config option
DEBUG_RWSEMS.

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>