KGDB fixes for amd64 and aarch64.
- Update the amd64 kernel support to recognize mchk_calltrap as a
trapframe generator.
- Remove some unneeded headers from fbsd-kld.c.
- Various fixes to get stack traces working for aarch64 kernels:
- Map the LR register from the PCB to PC instead of LR.
- Skip the PC register from the PCB as it isn't initialized to anything.
- Correct the register cache map for the PCB. The old one had the
offsets of pcb_sp and pcb_pc reversed.
- Don't map all of the saved general purpose registers in a
trapframe to X1 rather than X0 .. X29.
- Use correct name for el0 trapframe entry points.
Reviewed by: pizzamig (maintainer)
Differential Revision: https://reviews.freebsd.org/D13977
Approved by: ports-secteam (swills)
c2d9b63b55