MIPS: include linux/types.h

The file uses u16 type but doesn't include its definition explicitly

I was getting this error when including this header in my driver:

arch/mips/include/asm/mipsregs.h:644:33: error: unknown type name ‘u16’

Signed-off-by: Qais Yousef <[e-mail]>
Reviewed-by: Steven J. Hill <[e-mail]>
Acked-by: David Daney <[e-mail]>
Signed-off-by: John Crispin <[e-mail]>
Patchwork: http://patchwork.linux-mips.org/patch/6212/

arch/mips/include/asm/mipsregs.h

···
 #define _ASM_MIPSREGS_H
 
 #include <linux/linkage.h>
+#include <linux/types.h>
 #include <asm/hazards.h>
 #include <asm/war.h>