MIPS: Malta: hang on halt

MIPS: Malta: hang on halt

When the system is halted it makes little sense to reset it. Instead,
hang by executing an infinite loop.

[ralf@linux-mips.org: Remove printk from mips_machine_halt() - this is not
the place to communicate with the user.]

Suggested-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6906/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>