MIPS: Fix syscall tracing interface

Fix pointer computation for stack-based arguments.
Signed-off-by: NLars Persson <larper@axis.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6620/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/syscall.h

@@ -40,14 +40,14 @@ static inline unsigned long mips_get_syscall_arg(unsigned long *arg,
 
 #ifdef CONFIG_32BIT
 	case 4: case 5: case 6: case 7:
-		return get_user(*arg, (int *)usp + 4 * n);
+		return get_user(*arg, (int *)usp + n);
 #endif
 
 #ifdef CONFIG_64BIT
 	case 4: case 5: case 6: case 7:
 #ifdef CONFIG_MIPS32_O32
 		if (test_thread_flag(TIF_32BIT_REGS))
-			return get_user(*arg, (int *)usp + 4 * n);
+			return get_user(*arg, (int *)usp + n);
 		else
 #endif
 			*arg = regs->regs[4 + n];