package/linknx: bump to version 0.0.1.37

package/linknx: bump to version 0.0.1.37

- Remove patch, not needed since:
  https://github.com/linknx/linknx/commit/6166831eff645f21a7fd22ec3f7855f36005b8d9
- Needs iconv.h since version 0.0.1.34 and
  https://github.com/linknx/linknx/commit/2cc3a93dcf2703b3b418e0a99975f556354fb1b1
- Add a patch to fix link with libiconv
- Disable cppunit (autodetect by default), added with:
  https://github.com/linknx/linknx/commit/ee2efcde549dda82fdabde4af6d08871689cbb61

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