Updates for miscellaneous x86 areas:
- Reserve a new boot loader type for barebox which is usally used on ARM
and MIPS, but can also be utilized as EFI payload on x86 to provide
watchdog-supervised boot up.
- Consolidate the native and compat 32bit signal handling code and split
the 64bit version out into a separate source file
- Switch the ESPFIX random usage to get_random_long().