tools/power/acpi: close file only if it is open

The logic on the test for a valid fd to close is incorrect.
This was just a mistake and was pointed out by Colin Ian King.

Link: https://patchwork.kernel.org/patch/8620201/
Original-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

tools/power/acpi/tools/acpidbg/acpidbg.c

@@ -375,7 +375,7 @@ void usage(FILE *file, char *progname)
 
 int main(int argc, char **argv)
 {
-	int fd = 0;
+	int fd = -1;
 	int ch;
 	int len;
 	int ret = EXIT_SUCCESS;
@@ -430,7 +430,7 @@ int main(int argc, char **argv)
 	acpi_aml_loop(fd);
 
 exit:
-	if (fd < 0)
+	if (fd >= 0)
 		close(fd);
 	if (acpi_aml_batch_cmd)
 		free(acpi_aml_batch_cmd);