atmel-ssc: fix misuse of dev_dbg when requested ssc instance is not found

atmel-ssc: fix misuse of dev_dbg when requested ssc instance is not found

The ssc pointer is not valid when the id is not found in the list.
Convert the message from a debug one into an error message and avoid
dereferencing the bad pointer.

Signed-off-by: Hans-Christian Egtvedt <[email protected]>
Cc: Kay Sievers <[email protected]>
Cc: Huang Weiyi <[email protected]>
Acked-by: Haavard Skinnemoen <[email protected]>
Cc: David Brownell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>