Enable multiboot on non-pc.

	* conf/i386-coreboot.rmk, conf/i386-pc.rmk (pkglib_MODULES): Move
	multiboot.mod and multiboot2.mod to ...
	* conf/i386.rmk (pkglib_MODULES): ... here.
	* conf/i386-coreboot.rmk, conf/i386-pc.rmk (multiboot_mod_SOURCES):
	Moved to ...
	* conf/i386.rmk (multiboot_mod_SOURCES): .. here.
	* conf/i386-coreboot.rmk, conf/i386-pc.rmk (multiboot_mod_CFLAGS):
	Moved to ...
	* conf/i386.rmk (multiboot_mod_CFLAGS): .. here.
	* conf/i386-coreboot.rmk, conf/i386-pc.rmk (multiboot_mod_ASFLAGS):
	Moved to ...
	* conf/i386.rmk (multiboot_mod_ASFLAGS): .. here.
	* conf/i386-coreboot.rmk, conf/i386-pc.rmk (multiboot_mod_LDFLAGS):
	Moved to ...
	* conf/i386.rmk (multiboot_mod_LDFLAGS): .. here.
	* conf/x86_64-efi.rmk (pkglib_MODULES): Remove ata.mod and
	relocator.mod.
	(ata_mod_SOURCES): Removed.
	(ata_mod_CFLAGS): Likewise.
	(ata_mod_LDFLAGS): Likewise.
	(relocator_mod_SOURCES): Removed.
	(relocator_mod_CFLAGS): Likewise.
	(relocator_mod_ASFLAGS): Likewise.
	(relocator_mod_LDFLAGS): Likewise.
	Include i386.mk.
	* include/grub/x86_64/multiboot.h: New file.
	* loader/i386/multiboot.c (grub_multiboot_boot) [GRUB_MACHINE_EFI]:
	Terminate EFI.