[PATCH] libata: wrong sizeof for BUFFER

I have reproduced the AE_AML_BUFFER_LIMIT exception mentioned in
<http://bugzilla.kernel.org/show_bug.cgi?id=7689> basing on the SSDT ASL
code and libata ata_acpi_push_id() code.  There is an oversight in
ata_acpi_push_id() causing the exception.  The following update fixes it:

Signed-off-by: Fiodor Suietov <fiodor.f.suietov@intel.com>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>