kmod: workaround for microblaze ld bug

Add a workaround for a microblaze specific ld bug to avoid
segfault.

Fixes:
  http://autobuild.buildroot.net/results/aef1b915ffd3e5678af8682727c22c5618edfd89



[Peter: force --gc-sections configure check to false instead of patching
 	configure]
Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>