Remove mios-simulator-version-min from default iOS configuration

Remove mios-simulator-version-min from default iOS configuration

* iOS 6 and 7 got its last updates 2014.
* Adding -mios-simulator-version-min=14.0 to the configure command leads to two occurences of this parameter during compilation.
* So lets remove this values to allow a robust configuration from outside and avoid updates here in the future.

CLA: trivial

Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/23344)