Fix syntax errors in rvfi_csrw_check.sv
`csrget(`RISCV_FORMAL_CSRW_NAME, rmask) Got expanded into: rvfi.csr_mcycle_ rmask Because of the extra space, this resulted in: [csrw_mcycle_ch0] base: rvfi_csrw_check.sv:56: ERROR: syntax error, unexpected TOK_ID