[entropy_src/dv] Map testplan elements to tests
[entropy_src/dv] Map testplan elements to tests

In addition to specifying which test satisfies the various elements of
the entropy_src testplan requirements, this commit also updates the
"firmware" testplan section to reflect the latest naming and
configuration of the REGWEN/SW_REGUPD registers.

Signed-off-by: Martin Lueker-Boden <7e82c17fafb3b7b91b3c3396a2f21a060e5a6c3d@wdc.com>

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