scmi: Add NVMEM Vendor Extension Protocol

commit cd5dc9cc615456667aaa14b5c7d74d41836fc903 from
https://github.com/nxp-auto-linux/linux



Added the NVMEM over SCMI Vendor Extension Protocol, which enables
NVMEM drivers to encapsulate their NVMEM read requests into packets
and send them to a SCMI platform that performs the reading and returns
the values on their behalf.

Issue: ALB-9554
Signed-off-by: Andrei Cherechesu <andrei.cherechesu@nxp.com>
Signed-off-by: Zhantao Tang <zhantao.tang@windriver.com>