linux-user: Fix MIPS indirect syscall handling

Change the number of argument for MIPS sys_syscall from 0 to 8. This
allows arguments for indirect syscalls to be processed correctly.
Signed-off-by: NRiku Voipio <riku.voipio@linaro.org>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NAn-Cheng Huang <ancheng@ubnt.com>

linux-user/main.c

@@ -1749,7 +1749,7 @@ void cpu_loop(CPUPPCState *env)
 #define MIPS_SYS(name, args) args,
 
 static const uint8_t mips_syscall_args[] = {
-	MIPS_SYS(sys_syscall	, 0)	/* 4000 */
+	MIPS_SYS(sys_syscall	, 8)	/* 4000 */
 	MIPS_SYS(sys_exit	, 1)
 	MIPS_SYS(sys_fork	, 0)
 	MIPS_SYS(sys_read	, 3)