driver core: dd: fix return value of __setup handler

stable inclusion
from stable-v5.10.110
commit acb96e62e690507e059fd8acd3d62858ef4a8366
bugzilla: https://gitee.com/openeuler/kernel/issues/I574AL

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=acb96e62e690507e059fd8acd3d62858ef4a8366

--------------------------------

[ Upstream commit f2aad547 ]

When "driver_async_probe=nulltty" is used on the kernel boot command line,
it causes an Unknown parameter message and the string is added to init's
environment strings, polluting them.

  Unknown kernel command line parameters "BOOT_IMAGE=/boot/bzImage-517rc6
  driver_async_probe=nulltty", will be passed to user space.

 Run /sbin/init as init process
   with arguments:
     /sbin/init
   with environment:
     HOME=/
     TERM=linux
     BOOT_IMAGE=/boot/bzImage-517rc6
     driver_async_probe=nulltty

Change the return value of the __setup function to 1 to indicate
that the __setup option has been handled.

Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru
Fixes: 1ea61b68 ("async: Add cmdline option to specify drivers to be async probed")
Cc: Feng Tang <feng.tang@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Reported-by: NIgor Zhbanov <i.zhbanov@omprussia.ru>
Reviewed-by: NFeng Tang <feng.tang@intel.com>
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20220301041829.15137-1-rdunlap@infradead.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYu Liao <liaoyu15@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/base/dd.c

@@ -771,7 +771,7 @@ static int __init save_async_options(char *buf)
 		pr_warn("Too long list of driver names for 'driver_async_probe'!\n");
 
 	strlcpy(async_probe_drv_names, buf, ASYNC_DRV_NAMES_MAX_LEN);
-	return 0;
+	return 1;
 }
 __setup("driver_async_probe=", save_async_options);