patch tinydtls to accept a 32 byte PSK
patch tinydtls to accept a 32 byte PSK

Signed-off-by: Simon Thompson <cabe4a95f00ad8335415168991eeb3c94036510f@imgtec.com>

DavidAntliff/AwaLWM2M,DavidAntliff/AwaLWM2M,DavidAntliff/AwaLWM2M,DavidAntliff/AwaLWM2M,FlowM2M/AwaLWM2M,FlowM2M/AwaLWM2M,FlowM2M/AwaLWM2M,FlowM2M/AwaLWM2M