toolchain: musl: disable crypt size hack by default

toolchain: musl: disable crypt size hack by default

Enable this option and thus re-include crypt() support for the SHA256,
SHA512 and Blowfish ciphers on all devices. According to commit
9365745f8e7b ("musl: add a hack to remove unused crypt() algorithms,
saves ~14k after lzma") it should add about ~14k to the resulting image,
which seems to be a reasonable size increase for consistent crypt()
support.

Decided to not remove this hack completely as it might be still useful
for people trying to fit custom images onto smaller devices and the
patch is rather simple so we can afford to keep it for now.

References: https://github.com/openwrt/openwrt/pull/1331
Signed-off-by: Petr Štetiar <ynezz@true.cz>