intel-rst: Use ACPI_FAILURE() macro instead !ACPI_SUCCESS() for error checking

ACPI_SUCCESS is defined as:
#define ACPI_SUCCESS(a)			(!(a))

There is no need for the the double ! since there is already a macro
defined for failures: ACPI_FAILURE()

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@gmail.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>