ipmi_si: Remove bogus err_free label

There is no more 'free' in the error path, so drop the label and
return errors inline.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Message-Id: <20210402174334.13466-3-andriy.shevchenko@linux.intel.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>