Revert "coresight: etm4x: Add support to enable ETMv4.2"

This reverts commit c49d8ee4.

This is a preparation change for merging android-4.14.111 into
msm-4.14 branch.

Equivalent logic was already submitted into msm-4.14 and this
change affects creation of coresight-etm sysfs nodes.

Change-Id: Ie27f29442a82ef525af9ac49598d1b74c009faf7
Signed-off-by: Blagovest Kolenichev <bkolenichev@codeaurora.org>