ASoC: rt5663: Change the dev getting function in rt5663_irq

In the irq handler "rt5663_irq", while the codec is not initialized,
rt5663->codec will be null, and it will cause the kernel panic in the debug
print enabled.

Signed-off-by: Oder Chiou <oder_chiou@realtek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>