[sysrst_ctrl] Spell out all implicit 0 reset values in multifield CSRs
[sysrst_ctrl] Spell out all implicit 0 reset values in multifield CSRs

Some fields of multifield CSRs have a 0x1 reset value. In those cases,
all other fields are assigned X in the documentation if no explicit
reset value is specified.

This patch therefore spells out these reset values explicitly.

Signed-off-by: Michael Schaffner <a005a2d3342a687ea2d05360c953107acbe83e08@google.com>

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