[ARM] Fix pr84826.c failure for thumb1

*** gcc/testsuite/ChangeLog ***

2018-03-23  Sudakshina Das  <sudi.das@arm.com>

	PR target/84826
	* gcc.target/arm/pr84826.c: Add dg directive.

From-SVN: r258805

gcc/testsuite/ChangeLog

+2018-03-23  Sudakshina Das  <sudi.das@arm.com>
+
+	PR target/84826
+	* gcc.target/arm/pr84826.c: Add dg directive.
+
 2018-03-23  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/85033

gcc/testsuite/gcc.target/arm/pr84826.c

 /* { dg-do compile } */
+/* { dg-require-effective-target arm_thumb2_ok } */
 /* { dg-options "-Ofast -fstack-clash-protection" } */
 
 void d (void *);