The patch re-arch boot component header files by:
- moving multiboot.h from include/arch/x86/ to boot/include/ and keep
this header for multiboot1 protocol data struct only;
- moving multiboot related MACROs in cpu_primary.S to multiboot.h;
- creating an independent boot.h to store acrn specific boot information
for other files' reference;
Tracked-On: #4419
Signed-off-by: Victor Sun <victor.sun@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
