arm64: dts: ti: k3-am625-phyboard-lyra-rdk: Lower I2C1 frequency

The gpio-expander on i2c-1 has a maximum frequency of 100kHz. Update our
main_i2c1 frequency to allow the nxp,pcf8574 gpio-expander to function
properly.

Signed-off-by: Garrett Giordano <ggiordano@phytec.com>
Reviewed-by: Wadim Egorov <w.egorov@phytec.de>
Link: https://lore.kernel.org/r/20231204222811.2344460-1-ggiordano@phytec.com


Signed-off-by: Nishanth Menon <nm@ti.com>