crypto: ice: Return from debug API if ICE device not available

ICE driver does not return from debug API even if ICE device is NULL.
This can potentially crash the device if called with null device.
Added statements to return if device is null.

Change-Id: Idc4b098b7c06fa3da2f8754ac936c88f298cd894
Signed-off-by: Dinesh K Garg <dineshg@codeaurora.org>