HEADSUP: panic: running without device atpic requires a local APIC on UEFI systems after 0b01d45783c3

Hi,

It seems that the recent improvements of ACPI detection (e0f3dc82727f 
and 0b01d45783c3) would leave the system in an unbootable state if the 
UEFI files are not being updated at the same time of "make 
installworld".  At early boot the kernel would panic with:

panic: running without device atpic requires a local APIC on UEFI systems

To recover a system in this state, at loader prompt, use:

unset hint.acpi.0.disabled
boot

(I think core.lua should be modified to be compatible with an older UEFI 
payload, possibly issuing a warning that gets logged; and this should be 
mentioned in UPDATING)

Cheers,