[PATCH 2/3] s390/smsgiucv_app: Remove function pointer cast

[Nathan Chancellor <nathan@kernel.org>]

Clang warns (or errors with CONFIG_WERROR) after enabling
-Wcast-function-type-strict by default:

  drivers/s390/net/smsgiucv_app.c:176:26: error: cast from 'void (*)(const void *)' to 'void (*)(struct device *)' converts to incompatible function type [-Werror,-Wcast-function-type-strict]
    176 |         smsg_app_dev->release = (void (*)(struct device *)) kfree;
        |                                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  1 error generated.

Add a standalone function to fix the warning properly, which addresses
the root of the warning that these casts are not safe for kCFI.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 drivers/s390/net/smsgiucv_app.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/s390/net/smsgiucv_app.c b/drivers/s390/net/smsgiucv_app.c
index 0a263999f7ae..390aba4ef7ad 100644
--- a/drivers/s390/net/smsgiucv_app.c
+++ b/drivers/s390/net/smsgiucv_app.c
@@ -64,6 +64,11 @@ static void smsg_app_event_free(struct smsg_app_event *ev)
 	kfree(ev);
 }
 
+static void smsg_app_free_dev(struct device *dev)
+{
+	kfree(dev);
+}
+
 static struct smsg_app_event *smsg_app_event_alloc(const char *from,
 						   const char *msg)
 {
@@ -173,7 +178,7 @@ static int __init smsgiucv_app_init(void)
 	}
 	smsg_app_dev->bus = &iucv_bus;
 	smsg_app_dev->parent = iucv_root;
-	smsg_app_dev->release = (void (*)(struct device *)) kfree;
+	smsg_app_dev->release = smsg_app_free_dev;
 	smsg_app_dev->driver = smsgiucv_drv;
 	rc = device_register(smsg_app_dev);
 	if (rc) {

-- 
2.44.0