Based on num_hid_devices, each sensor device is initialized. If
"no sensors" is initialized, amd_sfh work initialization and scheduling
doesn’t make sense and returns EOPNOTSUPP to stop driver probe. Hence,
add a check for "no sensors" enabled to handle the special case.

Fixes: 93ce5e02 ("HID: amd_sfh: Implement SFH1.1 functionality")
Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>