um: Fix tag order in stub_32.h

"static void inline" is the wrong way around, fix that.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: 9f0b4807 ("um: rework userspace stubs to not hard-code stub location")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>