coresight: catu: Support atclk

The atclk is an optional clock for the CoreSight CATU, but the driver
misses to initialize it.

This change enables atclk in probe of the CATU driver, and dynamically
control the clock during suspend and resume.

The checks for driver data and clocks in suspend and resume are not
needed, remove them.  Add error handling in the resume function.

Fixes: fcacb5c1 ("coresight: Introduce support for Coresight Address Translation Unit")
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Tested-by: James Clark <james.clark@linaro.org>
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/20250731-arm_cs_fix_clock_v4-v6-2-1dfe10bb3f6f@arm.com