This makes it possible to run Serenity with more than 64 MB of RAM.
Because each physical page is represented by a PhysicalPage object, and such
objects are allocated using kmalloc_eternal(), more RAM means more pressure
on kmalloc_eternal(), so we're gonna need a better strategy for this.
But for now, let's just celebrate that we can use the 128 MB of RAM we've
been telling QEMU to run with. :^)
Define the multiboot info struct properly so we don't have to grab at byte
offsets in the memory access checker code. Also print kernel command line
in init().
