Replace uses of sbadaddr with stval

[mhorne063_gmail.com]

Summary

As of privilege spec v1.10, sbadaddr has been subsumed by stval. Replace usages
of sbadaddr and rename the member of struct trapframe to reflect this.

The compiler would already substitute stval for sbadaddr, so there should be no actual
impact to the exception handler.

Test Plan

Built kernel and booted successfully in qemu.

[mhorne063_gmail.com]

sys/riscv/riscv/trap.c

327 ↗

(On Diff #52137)

Not sure this is the right phrasing. Maybe just "address"?

[markj]

sys/riscv/riscv/trap.c

327 ↗

(On Diff #52137)

I think what's there is fine, or maybe "trap value". We don't know what stval is supposed to represent if the exception type is not recognized, so "address" seems presumptive to me.

328 ↗

(On Diff #52137)

Fix indentation while here?

396 ↗

(On Diff #52137)

Ditto.

[mhorne063_gmail.com]

sys/riscv/riscv/trap.c

327 ↗

(On Diff #52137)

Fair point. Trap value is probably the most straightforward then.