crypto: ice: Sanitize the ice device return address.

Even if ICE device is not found it is possible
for list device API to return non NULL pointer
which will pass all NULL checks in code. Ensure
to return proper address or NULL.

Change-Id: I1465614b86f1415376b2adffeec6e4da1a33ddd5
Signed-off-by: Neeraj Soni <neersoni@codeaurora.org>