Probe the switch through DT instead of a platform device. This fixes
probe, as GPIO offsets are now properly accounted for.
Fixes the following issue:
[ 0.802953] 8021q: 802.1Q VLAN Support v1.8
[ 0.810518] rtl8366_smi: gpio_request failed for 18, err=-517
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>