coresight: cti: Remove hw_enabled flag

coresight: cti: Remove hw_enabled flag

The enable_req_count field already tracks whether the CTI device is
enabled.  A non-zero value indicates that the device is active, the
hw_enabled flag is redundant if so.

Remove hw_enabled and update cti_is_active() to check enable_req_count.
Replace open-coded enable_req_count checks with cti_is_active().

Reviewed-by: Mike Leach <mike.leach@arm.com>
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20260226-arm_coresight_cti_refactor_v1-v2-7-b30fada3cfec@arm.com