riscv: Print stval in dump_regs for fatal exceptions

[jhb]

Summary

Sponsored by: DARPA
Obtained from: CheriBSD

[mhorne]

sys/riscv/riscv/trap.c

344

We do print sepc in dump_regs() as well. To me it seems more useful to have both values in this message, or neither.

[jhb]

sys/riscv/riscv/trap.c

344

Ok. I'm a bit torn actually on whether it's useful to duplicate info. If you only had the panic message without dump_regs for some reason then that might be a reason, or if you are categorizing panics based on the panic message (but the addresses are likely to not have enough of a pattern for that to be useful?)

Also, the load and store access fault's above should also be consistent presumably and print the address if this one does. Perhaps for now it would be best to just add the new line to dump_regs in this diff and leave the other changes alone?

[jhb]

Drop panic message changes