Removed the signal csr_access.

Created by: silabs-oysteink

CSR will be read for every cycle a CSR insn is in EX. Using ex_wb_pipe.rf_wdata in CSR read-modify-write, as this was using the flopped rdata which does not exist anymore (and was wrong).

Purposely not SEC clean. Passes ci_check (with ISS disabled)

Signed-off-by: Oystein Knauserud Oystein.Knauserud@silabs.com