coresight-etm4x: Adding CoreSight ETM4x driver

This driver manages the CoreSight ETMv4 (Embedded Trace Macrocell) IP block
to support HW assisted tracing on ARMv7 and ARMv8 architectures.

Change-Id: I741e05926f6f5fd4afa01a016d50a2c984910ff6
Signed-off-by: Pratik Patel <pratikp@codeaurora.org>
Signed-off-by: Kaixu Xia <xiakaixu@huawei.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Git-commit: 2e1cdfe184b5202d51e0611d7a051e2bea303946
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Shashank Mittal <mittals@codeaurora.org>