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 <[e-mail]>
Acked-by: Alan Tull <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/fpga/altera-cvp.c

···
 	if (ret)
 		goto err_unmap;
 
-	ret = driver_create_file(&altera_cvp_driver.driver,
-				 &driver_attr_chkcfg);
-	if (ret) {
-		dev_err(&pdev->dev, "Can't create sysfs chkcfg file\n");
-		fpga_mgr_unregister(mgr);
-		goto err_unmap;
-	}
-
 	return 0;
 
 err_unmap:
···
 	struct altera_cvp_conf *conf = mgr->priv;
 	u16 cmd;
 
-	driver_remove_file(&altera_cvp_driver.driver, &driver_attr_chkcfg);
 	fpga_mgr_unregister(mgr);
 	if (conf->map)
 		pci_iounmap(pdev, conf->map);
···
 	pci_write_config_word(pdev, PCI_COMMAND, cmd);
 }
 
-module_pci_driver(altera_cvp_driver);
+static int __init altera_cvp_init(void)
+{
+	int ret;
+
+	ret = pci_register_driver(&altera_cvp_driver);
+	if (ret)
+		return ret;
+
+	ret = driver_create_file(&altera_cvp_driver.driver,
+				 &driver_attr_chkcfg);
+	if (ret)
+		pr_warn("Can't create sysfs chkcfg file\n");
+
+	return 0;
+}
+
+static void __exit altera_cvp_exit(void)
+{
+	driver_remove_file(&altera_cvp_driver.driver, &driver_attr_chkcfg);
+	pci_unregister_driver(&altera_cvp_driver);
+}
+
+module_init(altera_cvp_init);
+module_exit(altera_cvp_exit);
 
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Anatolij Gustschin <[e-mail]>");