Rename WARN() to WARNING() to clear the namespace

We want to use WARN() as a variant of WARN_ON(), however a few drivers are
using WARN() internally.  This patch renames these to WARNING() to avoid the
namespace clash.  A few cases were defining but not using the thing, for those
cases I just deleted the definition.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Greg KH <greg@kroah.com>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>