riscv: Correct event usage for riscv_cpu_probe/setup

With having both an EVENT_SPY_SIMPLE setup for both riscv_cpu_probe and
riscv_cpu_setup we do not need the latter function to call the former
function as it will already have been done in time.

Fixes: 1c55d62f ("riscv: cpu: make riscv_cpu_probe to EVT_DM_POST_INIT_R callback")
Tested-by: Milan P. Stanić <mps@arvanta.net>
Signed-off-by: Tom Rini <trini@konsulko.com>