platform/x86: hp-wmi: Fix cast to smaller integer type warning

Fix the following compiler warning:

drivers/platform/x86/hp/hp-wmi.c:551:24: warning: cast to smaller integer
   type 'enum hp_wmi_radio' from 'void *' [-Wvoid-pointer-to-enum-cast]

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230123132824.660062-1-hdegoede@redhat.com