linux-imx

arm64: dts: Do not override power-domains node of dsp

Because we've separated power domain enablement for DSP (DAI related
power-domains are now enabled in FSL DAI node) there is no need
to override power-domains node.

Note that IRQSTR_DSP power-domain was missing from initial dsp
description so add it now.

Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>