dmaengine: zynqmp_dma: Add shutdown operation support

Add shutdown callback to ensure that DMA operations are properly stopped
and resources are released during system shutdown or kexec operations.
Fix incorrect PM state handling in the remove function that was causing
clock disable warnings during the shutdown operations, which was not
implemented earlier. The original logic used pm_runtime_enabled() check
after calling the pm_runtime_disable(), would always evaluate to true
after the disable call, which leads to unconditionally calling the
runtime_suspend regardless of the device's actual power state.

During shutdown, the device may already be suspended with clock disabled
from the autosuspend timer, causing the clock framework to warn about
the double-disable attempt. The pm_runtime_active() function checks the
actual device power state rather than the PM subsystem's enabled/disabled
status. ensuring the runtime_suspend is only called when the device is in
active power state. This prevents clock warnings during shutdown while
maintaining proper cleanup during normal remove operations.

Signed-off-by: Abin Joseph <abin.joseph@amd.com>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Link: https://lore.kernel.org/r/20250722070255.28944-1-abin.joseph@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>