drivers: dma_mcux_lpc: Fix omitted interrupt config

Add the invocation of an interrupt config function
(config->irq_config_func). Absence of this call results in the DMA
driver not being able to service interrupts raised by the DMA
peripheral.

This case was observed on the i.MX RT685's HiFi 4 DSP domain, where DMA
was not functional because of this.

Signed-off-by: Vit Stanicek <vit.stanicek@nxp.com>