arm64: dts: imx8mq-librem5: fix mipi_csi description

Properties are not documented so lead to the following error:
'#address-cells', '#size-cells', 'interrupts' do not match any of the regexes: 'pinctrl-[0-9]+'

Fix this by removing unneeded properties.

Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>