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

This reverts commit 2636ccec.

This is a preparation change for merging android-4.19.34 into
msm-4.19 branch.

Equivalent logic was already submitted into msm-4.19 and this
change affects creation of coresight-etm sysfs nodes.

Change-Id: Ic65c1f4707fef033e322e17db8522b6a96cf4e67
Signed-off-by: Ivaylo Georgiev <irgeorgiev@codeaurora.org>