fpga: fpga-bridge: remove unnecessary null check in of_fpga_bridge_get

Notice that bridge = to_fpga_bridge(dev); expands to:

bridge = container_of(dev, struct fpga_bridge, dev);

and container_of is never null, so this null check is
unnecessary.

Addresses-Coverity-ID: 1397912
Reported-by: Alan Tull <atull@kernel.org>
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Reviewed-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>