core: arm: sm: fix PSCI reset
core: arm: sm: fix PSCI reset

PSCI reset entry must call psci_system_reset(), not
psci_system_off().

Signed-off-by: Peng Fan <d3c162a96b7fb54e5d94bc77bc2c7cbbce10806f@nxp.com>
Reviewed-by: Jens Wiklander <7706914404370d7502c27a0eff493dcf491feb51@linaro.org>
Reviewed-by: Etienne Carriere <f21bc5b8f3ea1962eb45af359f1abea6578cab94@linaro.org>
[jf: Rebase, reword commit message]
Signed-off-by: Jerome Forissier <ced78d268b4c9a0a20a59a9feeebd2ad90da03d3@linaro.org>

pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os