arm64: dts: imx8mq-librem5: Remove invalid charger properties

arm64: dts: imx8mq-librem5: Remove invalid charger properties

Per bq25890.yaml, 'phys', 'ti,use-vinmin-threshold', 'ti,vinmin-threshold'
are not valid properties.

Remove them to fix the following schema warning:

imx8mq-librem5-r2.dtb: charger@6a: Unevaluated properties are not allowed ('phys', 'ti,use-vinmin-threshold', 'ti,vinmin-threshold' were unexpected)
	from schema $id: http://devicetree.org/schemas/power/supply/bq25890.yaml#

Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>