riscv: Fix fill_callchain return value

perf_callchain_store return 0 on success, -1 otherwise,
fix fill_callchain to return correct bool value.

Fixes: dbeb90b0 ("riscv: Add perf callchain support")
Signed-off-by: Nikita Shubin <n.shubin@yadro.com>
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/kernel/perf_callchain.c

@@ -68,7 +68,7 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
 
 static bool fill_callchain(void *entry, unsigned long pc)
 {
-	return perf_callchain_store(entry, pc);
+	return perf_callchain_store(entry, pc) == 0;
 }
 
 void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,