Reduce the number of checks and goto labels related to error handling
in acpi_os_execute() and drop the status local variable, which turns
out to be redundant, from it.

No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>