riscv: dts: sophgo: Add i2c device support for sg2042

The i2c ip of sg2042 is a standard Synopsys i2c ip, which is already
supported by the mainline kernel.

Add i2c device node for sg2042.

Reviewed-by: Chen Wang <unicorn_wang@outlook.com>
Tested-by: Chen Wang <unicorn_wang@outlook.com>
Link: https://lore.kernel.org/r/IA1PR20MB49530E59974AF0FCA4FAB6DBBBB72@IA1PR20MB4953.namprd20.prod.outlook.com


Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
Signed-off-by: Chen Wang <unicorn_wang@outlook.com>