Originally, the multiboot info struct was copied in the early assembly
language code. This code is moved to a C function in multiboot.c for
two reasons:
1. It's about to get more complicated, as we want the ability to use
a multiboot-provided memory map if available, and
2. this will faciliate its sharing between 32- and 64-bit subarches.
Signed-off-by: Charles E. Youse <charles.youse@intel.com>