Device can only be started if firmware is loaded, as per Skeleton
rawdev driver semantics. This patch fixes original implementation
which attempted to start the device without loading firmware.
Fixes: 55ca1b0f2151 ("raw/skeleton: add test cases")
Cc: shreyansh.jain@nxp.com
Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>