HID: intel-ish-hid: Fix -Wcast-function-type-strict in devm_ishtp_alloc_workqueue()

Clang warns (or errors with CONFIG_WERROR=y / W=e):

drivers/hid/intel-ish-hid/ipc/ipc.c:935:36: error: cast from 'void (*)(struct workqueue_struct *)' to 'void (*)(void *)' converts to incompatible function type [-Werror,-Wcast-function-type-strict]
935 | if (devm_add_action_or_reset(dev, (void (*)(void *))destroy_workqueue,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/device/devres.h:168:34: note: expanded from macro 'devm_add_action_or_reset'
168 | __devm_add_action_or_ireset(dev, action, data, #action)
| ^~~~~~

This warning is pointing out a kernel control flow integrity (kCFI /
CONFIG_CFI=y) violation will occur due to this function cast when the
destroy_workqueue() is indirectly called via devm_action_release()
because the prototype of destroy_workqueue() does not match the
prototype of (*action)().

Use a local function with the correct prototype to wrap
destroy_workqueue() to resolve the warning and CFI violation.

Reported-by: kernel test robot <[e-mail]>
Closes: https://lore.kernel.org/oe-kbuild-all/[e-mail]/
Closes: https://github.com/ClangBuiltLinux/linux/issues/2139
Fixes: 0d30dae38fe0 ("HID: intel-ish-hid: Use dedicated unbound workqueues to prevent resume blocking")
Signed-off-by: Nathan Chancellor <[e-mail]>
Acked-by: Srinivas Pandruvada <[e-mail]>
Reviewed-by: Zhang Lixu <[e-mail]>
Signed-off-by: Jiri Kosina <[e-mail]>

drivers/hid/intel-ish-hid/ipc/ipc.c

···
 	.dma_no_cache_snooping = _dma_no_cache_snooping
 };
 
+static void ishtp_free_workqueue(void *wq)
+{
+	destroy_workqueue(wq);
+}
+
 static struct workqueue_struct *devm_ishtp_alloc_workqueue(struct device *dev)
 {
 	struct workqueue_struct *wq;
···
 	if (!wq)
 		return NULL;
 
-	if (devm_add_action_or_reset(dev, (void (*)(void *))destroy_workqueue,
-				     wq))
+	if (devm_add_action_or_reset(dev, ishtp_free_workqueue, wq))
 		return NULL;
 
 	return wq;