mips: Fix printk typos in arc/mips

Correct spelling "platfom" to "platform", "deactived" to "deactivated"
and "deprectated" to "deprecated" in arch/mips directory.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>