Move check_file to os/$platform section

Keep check_file_generic() in shared code base, and allow special case
code in check_file() in os section. In future, macOS will have
additional checks in check_file().

Linux and FreeBSD wrappers just calls check_file_generic().

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Jorgen Lundman <lundman@lundman.net>
Closes #12385

cmd/zpool/os/freebsd/zpool_vdev_os.c

@@ -116,3 +116,9 @@ after_zpool_upgrade(zpool_handle_t *zhp)
 		    "details.\n"), zpool_get_name(zhp));
 	}
 }
+
+int
+check_file(const char *file, boolean_t force, boolean_t isspare)
+{
+	return (check_file_generic(file, force, isspare));
+}

cmd/zpool/os/linux/zpool_vdev_os.c

@@ -410,3 +410,9 @@ void
 after_zpool_upgrade(zpool_handle_t *zhp)
 {
 }
+
+int
+check_file(const char *file, boolean_t force, boolean_t isspare)
+{
+	return (check_file_generic(file, force, isspare));
+}

cmd/zpool/zpool_util.h

@@ -131,6 +131,7 @@ boolean_t check_sector_size_database(char *path, int *sector_size);
 void vdev_error(const char *fmt, ...) __attribute__((format(printf, 1, 2)));
 int check_file(const char *file, boolean_t force, boolean_t isspare);
 void after_zpool_upgrade(zpool_handle_t *zhp);
+int check_file_generic(const char *file, boolean_t force, boolean_t isspare);
 
 #ifdef	__cplusplus
 }

cmd/zpool/zpool_vdev.c

@@ -112,7 +112,7 @@ vdev_error(const char *fmt, ...)
  * not in use by another pool, and not in use by swap.
  */
 int
-check_file(const char *file, boolean_t force, boolean_t isspare)
+check_file_generic(const char *file, boolean_t force, boolean_t isspare)
 {
 	char  *name;
 	int fd;