misc/pvpanic: fix set driver data

Add again dev_set_drvdata(), but this time in devm_pvpanic_probe(), in order
for dev_get_drvdata() to not return NULL.

Fixes: 394febc9

 ("misc/pvpanic: Make 'pvpanic_probe()' resource managed")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mihai Carabas <mihai.carabas@oracle.com>
Link: https://lore.kernel.org/r/1629385946-4584-2-git-send-email-mihai.carabas@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>