[ARC] Fix tests asm constraints.

LRA doesn't like the 'X' constraint as used in our tests, remove it.

gcc/testsuite
2017-07-10  Claudiu Zissulescu  <claziss@synopsys.com>

	* gcc.target/arc/mulsi3_highpart-1.c: Remove 'X' constraint.
	* gcc.target/arc/mulsi3_highpart-2.c: Likewise.

From-SVN: r250096

gcc/testsuite/ChangeLog

+2017-07-10  Claudiu Zissulescu  <claziss@synopsys.com>
+
+	* gcc.target/arc/mulsi3_highpart-1.c: Remove 'X' constraint.
+	* gcc.target/arc/mulsi3_highpart-2.c: Likewise.
+
 2017-07-09  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR target/81313

gcc/testsuite/gcc.target/arc/mulsi3_highpart-1.c

@@ -7,7 +7,7 @@
 static int
 id (int i)
 {
-  asm ("": "+Xr" (i));
+  asm ("": "+r" (i));
   return i;
 }
 

gcc/testsuite/gcc.target/arc/mulsi3_highpart-2.c

@@ -9,7 +9,7 @@
 static int
 id (int i)
 {
-  asm ("": "+Xr" (i));
+  asm ("": "+r" (i));
   return i;
 }