Internal with two kinds of reference devices; One is the Nordic DFU/OTA supported and the other is DFU/OTA not upported. Add this DFU func to check device type to adjust all test cases. Change-Id: I2ae93fa05eff0e332fad30760efbdde5081f1bd8 Signed-off-by: Wei Tan <quic_weitan@quicinc.com>