efi: Drop handling of 'boot_info' configuration table

Some plumbing exists to handle a UEFI configuration table of type
BOOT_INFO but since we never match it to a GUID anywhere, we never
actually register such a table, or access it, for that matter. So
simply drop all mentions of it.

Tested-by: Tony Luck <tony.luck@intel.com> # arch/ia64
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>