[radio-spinel] exit if it fails to get radio channelmask from rcp (#3760)
[radio-spinel] exit if it fails to get radio channelmask from rcp (#3760)


chshu/openthread,abtink/openthread,chshu/openthread,bukepo/openthread,srickardti/openthread,abtink/openthread,openthread/openthread,bukepo/openthread,chshu/openthread,abtink/openthread,chshu/openthread,lanyuwen/openthread,bukepo/openthread,chshu/openthread,openthread/openthread,abtink/openthread,turon/openthread,openthread/openthread,librasungirl/openthread,srickardti/openthread,srickardti/openthread,turon/openthread,librasungirl/openthread,bukepo/openthread,lanyuwen/openthread,turon/openthread,lanyuwen/openthread,openthread/openthread,librasungirl/openthread,lanyuwen/openthread,jwhui/openthread,jwhui/openthread,chshu/openthread,jwhui/openthread,librasungirl/openthread,turon/openthread,jwhui/openthread,lanyuwen/openthread,srickardti/openthread,lanyuwen/openthread