MIPS: traps: Replace printk with pr_err for MC exceptions

printk should not be used without a KERN_ facility level

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8399/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>