apei(4): Simplify EINJ/ERST register access now that it's pre-mapped.

PR kern/58046

apei(4): Pre-map registers when compiling interpreter.

This way we don't have to worry about mapping them in nasty contexts
where access to uvm_km_alloc may not be allowed. Paves the way to
use ERST for saving dmesg on crash.

Exception: ACPI_ERST_MOVE_DATA still needs to do AcpiOsMapMemory.
We'll need to reserve a couple pages to avoid that.

PR kern/58046

apei(4): New driver for ACPI Platform Error Interfaces.

For now it is wired up only in x86 ALL kernels, and built as a module
for x86 and Arm. Once it gets a little more testing on machines with
APEI, I would like to flip it on by default.

PR kern/58046

apei(4): New driver for ACPI Platform Error Interfaces.

For now it is wired up only in x86 ALL kernels, and built as a module
for x86 and Arm. Once it gets a little more testing on machines with
APEI, I would like to flip it on by default.

PR kern/58046