Set dcsr.priv to M-mode on reset
Set dcsr.priv to M-mode on reset

Port of RI5CY commit 7f4a446f95f02f5ce517c0abe32b4095eb10c0de

AmbiML/ibex,lowRISC/ibex,AmbiML/ibex,lowRISC/ibex,lowRISC/ibex,lowRISC/ibex,AmbiML/ibex,AmbiML/ibex