fpga: fix sparse warnings in fpga-mgr and fpga-bridge

Fix up these sparse warnings:

drivers/fpga/fpga-mgr.c:189:21: warning: symbol '__fpga_mgr_get' was not declared. Should it be static?
drivers/fpga/fpga-bridge.c:30:12: warning: symbol 'bridge_list_lock' was not declared. Should it be static?

Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Acked-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>