platform/x86: dell-smbios: Fix memory leaks in build_tokens_sysfs()

We're freeing "value_name" which is NULL, so that's a no-op, but we
intended to free "location_name" instead.  And then we don't free the
names in token_location_attrs[0] and token_value_attrs[0].

Fixes: 33b9ca1e ("platform/x86: dell-smbios: Add a sysfs interface for SMBIOS tokens")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>