Add the static kernel boot environment, needed to actually boot this thing.

(Wasting 4k just as a temporary placeholder for a boot environment seems
a bit ridiculous, but hey.)

Tested: gxemul:

$ gxemul -e malta -d i:/home/adrian/work/freebsd/svn/mfsroot-rspro.img -C 4Kc /tftpboot/kernel.MALTA
On non-ACPI i386 mp_ncpus is initialized at SI_SUB_CPU, and this
prevents us from creating UMA_ZONE_PCPU zones earlier.

As bandaid shift initialization of counter(9) zone later.

Reviewed by:		kib
Reported & tested by:	Lytochkin Boris <lytboris gmail.com>