With commit 28d528c8 "ASoC: core: Remove pointless error on card
registration failure", the variable ret is no longer used in
soc_probe() and generates an unused variable warning during a build.
Signed-off-by: NJerry Snitselaar <dev@snitselaar.org>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>