wolfssl: make shared again

wolfssl: make shared again

Disable the usage of target specific CPU crypto instructions by default
to allow the package being shared again. Since WolfSSL does not offer
a stable ABI or a long term support version suitable for OpenWrt release
timeframes, we're forced to frequently update it which is greatly
complicated by the package being nonshared.

People who want or need CPU crypto instruction support can enable it in
menuconfig while building custom images for the few platforms that support
them.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>