Thank you @jyijyi very much! This solved the issue, now I can compile the drivers and find them under /sys/devices directory.
I did not have to change anything in \linux_kernel_modules\mangoh\board_red_dv3.c. or similar as you described. I pulled newest version from mangOH git, and there are no i2c_get_adapter(0) anymore. The 0 is replaced with some variable for each i2c_get_adapter().
Is this something that will be fixed in later versions? Since I am working with both WP8548 and WP7702 I guess I need to change the trigger.h file accordingly to what module I am using?