drivers: net: can: Fix for null ptr dereferencxe

Updated the code to ensure null pointer in not
dereferenced to cause memory violation.
Also, modified the banned api with a safer version.

Change-Id: I1087e08f9bc8cbf3eaaef4fb4c77c74ded0b1159
Signed-off-by: Raj Pandey <quic_rajpande@quicinc.com>