fpga: region: release of_parse_phandle nodes after use

commit 0f5eb1545907edeea7672a9c1652c4231150ff22 upstream.

Both fpga_region_get_manager() and fpga_region_get_bridges() call
of_parse_phandle(), but nothing calls of_node_put() on the returned
struct device_node pointers.  Make sure to do that to stop their
reference counters getting out of whack.

Fixes: 0fa20cdf ("fpga: fpga-region: device tree control for FPGA")
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>