ASoC: wm8962: Convert to devm_clk_get_optional()

Use the existing devm_clk_get_optional() helper instead of building a
similar construct on top of devm_clk_get() that fails to handle all
errors but -EPROBE_DEFER.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/c2a8a1a628804a4439732d02847e25c227083690.1634565564.git.geert+renesas@glider.be


Signed-off-by: Mark Brown <broonie@kernel.org>