Remove min_iov_compat_ver field as for now all versions are compatible.

Compatibility is determined by a series of rules and dynamic conditions
such as specific configurations.
In any case the minimum version requirement for compatibility is
an inadequate and obsolete approach which should be removed.

At this time compatibility can be assured across the currently available
versions.
Signed-off-by: Marco Chiappero <marco.chiappero@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>