Fix compiler warning about variable use before being initialized that
appears with gcc 11.1.0.
test/byte-stream-buffer.cpp:31:63: error: ‘data’ may be used uninitialized [-Werror=maybe-uninitialized]
Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>