fpga: altera-cvp: fix probing for multiple FPGAs on the bus

fpga: altera-cvp: fix probing for multiple FPGAs on the bus

Currently registering CvP managers works only for first probed CvP
device, for all other devices it is refused due to duplicated chkcfg
sysfs entry:

fpga_manager fpga3: Altera CvP FPGA Manager @0000:0c:00.0 registered
sysfs: cannot create duplicate filename '/bus/pci/drivers/altera-cvp/chkcfg'
CPU: 0 PID: 3808 Comm: bash Tainted: G           O      4.19.0-custom+ #5
Call Trace:
  dump_stack+0x46/0x5b
  sysfs_warn_dup+0x53/0x60
  sysfs_add_file_mode_ns+0x16d/0x180
  sysfs_create_file_ns+0x51/0x60
  altera_cvp_probe+0x16f/0x2a0 [altera_cvp]
  local_pci_probe+0x3f/0xa0
  ? pci_match_device+0xb1/0xf0
  pci_device_probe+0x116/0x170
  really_probe+0x21b/0x2c0
  driver_probe_device+0x4b/0xe0
  bind_store+0xcb/0x130
  kernfs_fop_write+0xfd/0x180
  __vfs_write+0x21/0x150
  ? selinux_file_permission+0xdc/0x130
  vfs_write+0xa8/0x1a0
  ? find_vma+0xd/0x60
  ksys_write+0x3d/0x90
  do_syscall_64+0x44/0xf0
  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  ...
 altera-cvp 0000:0c:00.0: Can't create sysfs chkcfg file
 fpga_manager fpga3: fpga_mgr_unregister Altera CvP FPGA Manager @0000:0c:00.0

Move chkcfg creation to module init as suggested by Alan.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Acked-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>