kselftest/arm64: Provide progress messages when signalling children

Especially when the test is configured to run for a longer time it can be
reassuring to users to see that the supervising program is running OK so
provide a message every second when the output timer expires.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221017144553.773176-3-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

tools/testing/selftests/arm64/fp/fp-stress.c

@@ -549,6 +549,9 @@ int main(int argc, char **argv)
 			all_children_started = true;
 		}
 
+		ksft_print_msg("Sending signals, timeout remaining: %d\n",
+			       timeout);
+
 		for (i = 0; i < num_children; i++)
 			child_tickle(&children[i]);