MIPS qemu at_keyboard support.

	MIPS qemu at_keyboard support.

	* gentpl.py (videoinkernel): Add qemu-mips.
	* grub-core/Makefile.am (KERNEL_HEADER_FILES): Add necessary headers.
	* grub-core/Makefile.core.def (kernel): Add at_keyboard and layout.
	* grub-core/kern/mips/qemu_mips/init.c (grub_machine_init): Init new
	modules.
	* grub-core/term/at_keyboard.c (grub_keyboard_controller_init)
	[GRUB_MACHINE_MIPS_QEMU_MIPS]: Don't consider original set.
	* grub-core/term/serial.c (grub_serial_register)
	[GRUB_MACHINE_MIPS_QEMU_MIPS]: Make com0 explicitly active.