power: supply: max17042: support standard shunt-resistor-micro-ohms DT property

power: supply: max17042: support standard shunt-resistor-micro-ohms DT property

shunt-resistor-micro-ohms is a standard property used to describe the
value of a shunt resistor required when measuring currents. Standard
properties should be used instead of vendor-specific ones of similar
intention when possible.

Try to read it from DT, and fall back to the vendor-specific property
maxim,rsns-microohm if unsuccessful for compatibility with existing
DTs.

Reviewed-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: André Draszik <andre.draszik@linaro.org>
Link: https://patch.msgid.link/20260302-max77759-fg-v3-8-3c5f01dbda23@linaro.org
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>