RISC-V: Fix testcase on rv64

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/attribute-10.c: Fix testcase on rv64.

From-SVN: r273968

gcc/testsuite/ChangeLog

+2019-08-01  Kito Cheng  <kito.cheng@sifive.com>
+
+	* gcc.target/riscv/attribute-10.c: Fix testcase on rv64.
+
 2019-07-31  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* g++.dg/diagnostic/delete1.C: New.

gcc/testsuite/gcc.target/riscv/attribute-10.c

 /* { dg-do compile } */
-/* { dg-options "-O2 -march=rv32im_s_sx_unexpectedstring -mabi=ilp32" } */
+/* { dg-options "-O2 -march=rv32i -march=rv32im_s_sx_unexpectedstring -mabi=ilp32" } */
 int foo()
 {
 }