There was no further information other than Rayfield will be taking on a role at "another company". No announcement about this new role has been made and Rayfield's LinkedIn profile still stated his position as "VP/GM Mobile Business Unit" at Nvidia at the time of this writing.
Growing competition among ARM chip makers, in addition to the efforts of Intel and AMD to hold x86 architecture against ARM has turned into a catalyst of a job carousel that has involved Apple, AMD, Intel, Qualcomm, TI, as well as component makers such as Synaptics.
Rayfield joined Nvidia in 2005 from Stretch. Prior to that he held executive positions in sales and business development at Texas Instruments, Growth Networks and Cisco.