Use LBIO on coreboot.

	Use LBIO on coreboot.

	* conf/i386-coreboot.rmk (kernel_img_SOURCES): Change
	kern/i386/multiboot_mmap.c to kern/i386/coreboot/mmap.c.
	* include/grub/i386/coreboot/memory.h (GRUB_LINUXBIOS_MEMBER_LINK):
	New declaration.
	* kern/i386/coreboot/init.c (grub_machine_init): Don't call
	grub_machine_mmap_init on coreboot.
	* kern/i386/coreboot/mmap.c (grub_linuxbios_table_iterate): Handle
	GRUB_LINUXBIOS_MEMBER_LINK.
	(grub_machine_mmap_iterate): Fix declaration.
	* kern/i386/coreboot/startup.S: Don't save mbi location on coreboot.