In r298230 the value of HEAP_MIN was changed from 3MB to 64MB. Correct a

comment that was still referencing the 3MB value.

Sponsored by:	Dell EMC Isilon
Discussed with:	jhb

sys/boot/i386/libi386/biosmem.c

@@ -200,7 +200,7 @@ bios_getmem(void)
 
     /*
      * If we have extended memory and did not find a suitable heap
-     * region in the SMAP, use the last 3MB of 'extended' memory as a
+     * region in the SMAP, use the last HEAP_MIN of 'extended' memory as a
      * high heap candidate.
      */
     if (bios_extmem >= HEAP_MIN && high_heap_size < HEAP_MIN) {