dmaengine: altera: Use IRQ-safe spinlock calls in the error paths as well

The patch edf10919 [dmaengine: altera: fix spinlock usage] missed to
change 2 occurrences of spin_unlock_bh() to spin_unlock_irqrestore().
This patch fixes this by moving to the IRQ-safe call in the error
paths as well.

Fixes: edf10919

 (dmaengine: altera: fix spinlock usage)
Signed-off-by: Stefan Roese <sr@denx.de>
Reviewed-by: Sylvain Lesne <lesne@alse-fr.com>
[add fixes tag and fix typo in log]
Signed-off-by: Vinod Koul <vinod.koul@intel.com>