ASoC: mchp-spdiftx: simplify locking around ctrl->ch_stat

Use a temporary variable to keep the AES3 value. With this a
spin_unlock_irqrestore() call has been removed from the final code.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20221117123750.291911-2-claudiu.beznea@microchip.com


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