x86: Show some EFI info with the bdinfo command

It is useful to see some basic EFI info with the command as it forms part
of the information about a board.

Add a hook for this and show the table address as a start.

While here, fix an invalid cast in setup_efi_info(). Note that this
function is using a data structure defined by Linux so we cannot change
it. Also note that ulong is used since this is the standard in U-Boot
(>6k uses), despite there being quite a bit of the more verbose uintptr_t
(930 uses).

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>