ZVOL: Make zvol_inhibit_dev module parameter platform-independent

The module parameter now is represented in FreeBSD sysctls list with
name: 'vfs.zfs.vol.inhibit_dev'. The default value is '0', same as on
Linux side.

Sponsored-by: vStack, Inc.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Rob Norris <rob.norris@klarasystems.com>
Signed-off-by: Fedor Uporov <fuporov.vstack@gmail.com>
Closes #17384

module/os/linux/zfs/zvol_os.c

@@ -1788,9 +1788,6 @@ zvol_fini(void)
 	ida_destroy(&zvol_ida);
 }
 
-module_param(zvol_inhibit_dev, uint, 0644);
-MODULE_PARM_DESC(zvol_inhibit_dev, "Do not create zvol device nodes");
-
 module_param(zvol_major, uint, 0444);
 MODULE_PARM_DESC(zvol_major, "Major number for zvol device");