cmd: optee_rpmb command for read/write of rpmb from optee

cmd: optee_rpmb command for read/write of rpmb from optee

Enable "optee_rpmb" command to write/read named persistent values
created on RPMB by opening session with OPTEE AVB TA.
This provides easy test for establishing a session with OPTEE
TA and storage of persistent data in MMC RPMB.

It includes following subcommands:

optee_rpmb read_pvalue:read persistent values on rpmb via OPTEE AVB TA
optee_rpmb write_pvalue:write persistent values on rpmb via OPTEE AVB
TA

Signed-off-by: Ruchika Gupta <ruchika.gupta@nxp.com>
[Rebased]
Signed-off-by: Priyanka Jain <priyanka.jain@nxp.com>