Revert "Add i.MX6 to CI"

This reverts commit 3d1c8cf32df36fccd6a5f4c0c40877bbe64610d7
Wasn't the latest configuration I had.

Change-Id: Ifd3068c086d97a3e037a0bdea589baa728c22afc
Reviewed-by: Simo Fält <simo.falt@digia.com>