fpga: manager: change api, don't use drvdata

Change fpga_mgr_register to not set or use drvdata.  This supports
the case where a PCIe device has more than one manager.

Add fpga_mgr_create/free functions.  Change fpga_mgr_register and
fpga_mgr_unregister functions to take the mgr struct as their only
parameter.

  struct fpga_manager *fpga_mgr_create(struct device *dev,
                const char *name,
                const struct fpga_manager_ops *mops,
                void *priv);
  void fpga_mgr_free(struct fpga_manager *mgr);
  int fpga_mgr_register(struct fpga_manager *mgr);
  void fpga_mgr_unregister(struct fpga_manager *mgr);

Update the drivers that call fpga_mgr_register with the new API.

Signed-off-by: Alan Tull <atull@kernel.org>
[Moritz: Fixup whitespace issue]
Reported-by: Jiuyue Ma <majiuyue@huawei.com>
Signed-off-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>