MIPS: traps: remove unused variable

flags is indeed unused.

Signed-off-by: Tony Wu <tung7970@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11699/


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