package/ebtables: fix runtime in case of BR2_KERNEL_64_USERLAND_32

package/ebtables: fix runtime in case of BR2_KERNEL_64_USERLAND_32

ebtables 2.0.11 no longer works correctly when userland is 32-bit and the
kernel is 64-bit. This used to work correctly in version 2.0.10-4.

Problem is twofold:
- ebtables itself was broken and needs to be patched
- buildroot needs to pass the correct flag again to indicate when we are in
  this situation

Signed-off-by: Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>