machine: imx6: remove not used fix
machine: imx6: remove not used fix

Some very outdated perf fix was still in the imx-base.inc. Remove it,
it's not needed anymore.

Signed-off-by: Stefan Christ <c04781dbce194802ec6a6311a1200fbcd0141e96@phytec.de>
Signed-off-by: Stefan Müller-Klieser <a3e08e35e4a42be768e7d0e76ae1ba321c2a66dd@phytec.de>

PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec