Sets or returns priority for system handlers 4 - 7
| PRI_4_3 | Priority of system handler 4, SecureFault |
| PRI_5_3 | Priority of system handler 5, SecureFault |
| PRI_6_3 | Priority of system handler 6, SecureFault |
| PRI_7_3 | Priority of system handler 7, SecureFault |