asus-laptop: remove redundant initializers

Initializing rv to AE_OK is pointless because later function results are
assigned to them and only then the variable is used

Signed-off-by: Giedrius Statkevičius <giedrius.statkevicius@gmail.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>