coresight: stm: Fix error parameter in stm

In stm_disable, "drvdata->base" instead of "drvdata" should
be passed to coresight_timeout.

Change-Id: I110727bb0f14cd4aa3f7adb78f462973dc1e4a54
Signed-off-by: Yuanfang Zhang <zhangyuanfang@codeaurora.org>