Assertions for CSR set/clear with rs1==0
Created by: silabs-oysteink
Added assertions to check that set/clear with rs1==0 will not change any bits in the following CSRs:
mstateen0 cputrl mseccfg pmpaddr0-63 pmpcfg0-15
Note that the assertion checking pmpaddr0-63 fails. An issue will be created for this.