x86/boot: introduce struct boot_module

x86/boot: introduce struct boot_module

This will introduce a new struct boot_module to provide a rich state
representation around modules provided by the boot loader. Support is for 64
boot modules, one held in reserve for Xen, and up to 63 can be provided by the
boot loader. The array of struct boot_modules will be accessible via a
reference held in struct boot_info.

A temporary `mod` parameter is included in struct boot_module to ease the
transition from using Multiboot v1 structures over to struct boot_module. Once
the transition is complete, the parameter will be dropped from the structure.

Signed-off-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Reviewed-by: Jason Andryuk <jason.andryuk@amd.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>