RISC-V/testsuite: Fix comment termination in pr105314.c

Add terminating `/' character missing from one of the test harness
command clauses in pr105314.c.  This causes no issue with compilation
owing to another comment immediately following, but would cause a:

pr105314.c:3:1: warning: "/*" within comment [-Wcomment]

message if warnings were enabled.

	gcc/testsuite/
	* gcc.target/riscv/pr105314.c: Fix comment termination.

gcc/testsuite/gcc.target/riscv/pr105314.c

@@ -1,5 +1,5 @@
 /* PR rtl-optimization/105314 */
-/* { dg-do compile } *
+/* { dg-do compile } */
 /* { dg-options "-O2" } */
 /* { dg-final { scan-assembler-not "\tbeq\t" } } */