hammer(8): Fix fallout from recent RB-tree change

Noticed-by: tuxillo
kernel/i386: Remove two unused math helper functions in ACPI.

We can divide and shift 64 bit integers just fine.

These would only be needed if ACPI_USE_NATIVE_DIVIDE (see ACPI
Programmer Reference, 7.5.4) wasn't set.
kernel/i386: Remove an unused ACPI prototype.
bsd-family-tree: Sync with FreeBSD (for DragonFly 3.6.1).