arm64: dts: imx8mq: enable Hantro G1/G2 VPU

Add the i.MX8MQ VPU module which comprises Hantro G1 and G2 video
decoder cores and a reset/control block.

Hook up the bus clock to the VPU power domain to enable handshakes, and
configure the core clocks to 600 MHz and the bus clock to 800 MHz by
default.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Ezequiel Garcia <ezequiel@collabora.com>
Tested-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>