acpi processor: remove superfluous warning message

This failure is very common on many platforms.  Handling it in the ACPI
processor driver is enough, and we don't need a warning message unless
CONFIG_ACPI_DEBUG is set.

Based on a patch from Zhang Rui.

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=13389

Signed-off-by: Frans Pop <elendil@planet.nl>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>