Uninitialized char* causes a sparse build-warning, fix it up by
initializing it to NULL.
Acked-by: NJohn Youn <johnyoun@synopsys.com>
Signed-off-by: NNicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: NFelipe Balbi <felipe.balbi@linux.intel.com>