net: qede: sanitize 'rc' in qede_add_tc_flower_fltr()

Explicitly set 'rc' (return code), before jumping to the
unlock and return path.

By not having any code depend on that 'rc' remains at
it's initial value of -EINVAL, then we can re-use 'rc' for
the return code of function calls in subsequent patches.

Only compile tested.

Signed-off-by: Asbjørn Sloth Tønnesen <ast@fiberby.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>