package/strongswan: bump to version 5.9.0

- Drop patches (already in version)
- wolfssl is an optional dependency since version 5.8.0 and
  https://github.com/strongswan/strongswan/commit/c92eade82c814e9f6b55f80d715bb51d28d5e1fb
- Update indentation of hash file (two spaces)

https://wiki.strongswan.org/versions/78



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>