Fix bougs PR 78170 failure for avr

The test defines int bitfields that are more than 16 bits wide, and this
fails for the avr with its 16 bit integer size. Therefore, require
effective target int32plus.

gcc/testsuite/

2016-11-03  Senthil Kumar Selvaraj  <senthil_kumar.selvaraj@atmel.com>

	* gcc.c-torture/execute/pr78170.c: Require int32plus.

From-SVN: r241809

gcc/testsuite/ChangeLog

+2016-11-03  Senthil Kumar Selvaraj  <senthil_kumar.selvaraj@atmel.com>
+
+	* gcc.c-torture/execute/pr78170.c: Require int32plus.
+
 2016-11-02  Max Filippov  <jcmvbkbc@gmail.com>
 
 	* gcc.c-torture/compile/20001226-1.c: Don't xfail on xtensa.

gcc/testsuite/gcc.c-torture/execute/pr78170.c

+/* { dg-require-effective-target int32plus } */
+
 /* PR tree-optimization/78170.
    Check that sign-extended store to a bitfield
    doesn't overwrite other fields.  */