driver core: Set fw_devlink to "permissive" behavior by default

Set fw_devlink to "permissive" behavior by default so that device links
are automatically created (with DL_FLAG_SYNC_STATE_ONLY) by scanning the
firmware.

This ensures suppliers get their sync_state() calls only after all their
consumers have probed successfully. Without this, suppliers will get
their sync_state() calls at late_initcall_sync() even if their consuer

Ideally, we'd want to set fw_devlink to "on" or "rpm" by default. But
that needs more testing as it's known to break some corner case
drivers/platforms.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: devicetree@vger.kernel.org
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200321210305.28937-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base/core.c

@@ -2345,7 +2345,7 @@ static int device_private_init(struct device *dev)
 	return 0;
 }
 
-static u32 fw_devlink_flags;
+static u32 fw_devlink_flags = DL_FLAG_SYNC_STATE_ONLY;
 static int __init fw_devlink_setup(char *arg)
 {
 	if (!arg)