coresight-etm: add CoreSight ETM/PTM driver

This driver manages CoreSight ETM (Embedded Trace Macrocell) that
supports processor tracing. Currently supported version are ARM
ETMv3.x and PTM1.x.

Signed-off-by: Pratik Patel <pratikp@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight-etm3x: adding missing error checking
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>