package/lttng-tools: remove no longer needed patch

This patch is already merged since the v2.7.0-rc1 version.

Fixes:
  http://autobuild.buildroot.net/results/0178e243eb27376d1507f1adde5d12bdbc0f352b


  (and many others)

Signed-off-by: Samuel Martin <s.martin49@gmail.com>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>