[MIPS] SMTC: Fix build error.

Fix compile warning (which becomes compile error due to -Werror).  Type of
argument "flags" for spin_lock_irqsave() was incorrect in some functions.

Signed-off-by: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>