fpga: bridge: fix kernel-doc

Fix the following warnings issued by the kernel-doc script:

drivers/fpga/fpga-bridge.c:99: warning: No description found for return value of 'of_fpga_bridge_get'
drivers/fpga/fpga-bridge.c:163: warning: No description found for return value of 'fpga_bridges_enable'
drivers/fpga/fpga-bridge.c:187: warning: No description found for return value of 'fpga_bridges_disable'
drivers/fpga/fpga-bridge.c:238: warning: No description found for return value of 'of_fpga_bridge_get_to_list'
drivers/fpga/fpga-bridge.c:268: warning: No description found for return value of 'fpga_bridge_get_to_list'

- Extend the return description of of_fpga_bridge_get() to include the
  case when try_module_get() fails.

Signed-off-by: Marco Pagani <marpagan@redhat.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/20230706142755.124879-3-marpagan@redhat.com


Signed-off-by: Xu Yilun <yilun.xu@intel.com>