ACPICA: Move check for valid Thread ID structure

This change moves the check for a valid Thread ID structure up a
few lines to insure that the check is made before the structure
is actually used.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>