[bug report] platform/x86: ISST: Add IOCTL default callback

[Dan Carpenter <error27@xxxxxxxxx>]

Hello Srinivas Pandruvada,

The patch 33c16dc1a2d1: "platform/x86: ISST: Add IOCTL default
callback" from Feb 10, 2023, leads to the following Smatch static
checker warning:

	drivers/platform/x86/intel/speed_select_if/isst_if_common.c:629 isst_if_def_ioctl()
	info: return a literal instead of 'ret'

drivers/platform/x86/intel/speed_select_if/isst_if_common.c
    615         case ISST_IF_MSR_COMMAND:
    616                 cmd_cb.cmd_size = sizeof(struct isst_if_msr_cmd);
    617                 cmd_cb.offset = offsetof(struct isst_if_msr_cmds, msr_cmd);
    618                 cmd_cb.cmd_callback = isst_if_msr_cmd_req;
    619                 ret = isst_if_exec_multi_cmd(argp, &cmd_cb);
    620                 break;
    621         default:
    622                 for (i = 0; i < ISST_IF_DEV_MAX; ++i) {
    623                         struct isst_if_cmd_cb *cb = &punit_callbacks[i];
    624                         int ret;
    625 
    626                         if (cb->def_ioctl) {
    627                                 ret = cb->def_ioctl(file, cmd, arg);
    628                                 if (!ret)
--> 629                                         return ret;

This returns the first time something succeeds.  Normally it would be
the other way around, where we return the first time something fails.
If this is really intentional it would be better to do an explicit
"return 0;"

    630                         }
    631                 }
    632                 break;
    633         }
    634 
    635         return ret;
    636 }

regards,
dan carpenter