[PowerPC] Fix kernel boot on powerpc

Recent changes have caused the vmspace objects to start coming from KVA
instead of direct-mapped memory on powerpc. As far as I can tell, this is
not actually a problem, so we should stop arbitrarily asserting that it is.

I do not know why this was not being triggered before.

Approved by:	jhibbits
Sponsored by:	Tag1 Consulting, Inc.

sys/powerpc/aim/mmu_oea.c

@@ -1703,7 +1703,6 @@ moea_pinit(mmu_t mmu, pmap_t pmap)
 	int	i, mask;
 	u_int	entropy;
 
-	KASSERT((int)pmap < VM_MIN_KERNEL_ADDRESS, ("moea_pinit: virt pmap"));
 	RB_INIT(&pmap->pmap_pvo);
 
 	entropy = 0;