coresight: Avoid casting void pointers

coresight: Avoid casting void pointers

We don't need to cast void pointers, such as the amba_id data. Assign to
a local variable to make the code prettier and also return NULL instead
of 0 to make sparse happy.

Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Joe Perches <joe@perches.com>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-21-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>