[fpv/pinmux] Add dio/mio_attr_o assertions
[fpv/pinmux] Add dio/mio_attr_o assertions

This PR adds assertions for d/mio_attr_o output based on the attr csr

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

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