coresight: remove duplicated enumeration

Both ETMv3 and ETMv4 drivers are declaring an 'enum etm_addr_type',
creating reduncancy.

This patch removes the enumeration from the driver files and adds
it to a common header.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>