Hello!
on x86_64:
CONFIG_HWMON is not enabled.
drivers/gpu/drm/nouveau/nouveau_hwmon.c: In function 'nouveau_hwmon_init': drivers/gpu/drm/nouveau/nouveau_hwmon.c:633:2: error: 'hwmon' undeclared (first use in this function)
I've attached a patch that fixes the build for me when using this config.