[dv/chip] fix same_csr_outstanding sequence assertion error
[dv/chip] fix same_csr_outstanding sequence assertion error

This mubi assertion error is because in csr tests, we randomly write
value to a mubi typed register.
Because internal design will treat non-mubi4 value as False, so we can
disable this assertion.

Signed-off-by: Cindy Chen <399ad771a111eac8923348b1e2af093034e5d4f1@opentitan.org>

lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan