[otbn,dv] Increase iteration of sw_errs_fatal_chk
[otbn,dv] Increase iteration of sw_errs_fatal_chk

This is needed because it's the only test where we set directly
set `CTRL` CSR to 1, making software errors fatal.

Signed-off-by: Canberk Topal <e6b05429a51cc3258c31cb1f7836595b60921a29@lowrisc.org>

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