[PATCH 2/2] perf cs-etm: Avoid printing warning in cs_etm_is_ete() check

[Leo Yan]

On Wed, Mar 08, 2023 at 09:48:43AM +0000, James Clark wrote:
> When checking for the presence of ETE, a register is read that may not
> be present on older kernels or if ETE isn't available. cs_etm_get_ro()
> will print a warning if it doesn't exist, so check for the existence
> first before accessing it.
> 
> Signed-off-by: James Clark <james.clark at arm.com>

Reviewed-by: Leo Yan <leo.yan at linaro.org>