ASoC: Intel: Skylake: Fix return for pm_runtime_get_sync()

pm_runtime_get_sync() will return a negative value in case of
error and can return postive value for success.  The return check
for pm_runtime_get_sync() must be less than 0, so fix it

Signed-off-by: Jeeja KP <jeeja.kp@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>