greybus: gb-beagleplay: Fix timeout handling in bootloader functions

wait_for_completion_timeout() returns the remaining jiffies
(at least 1) on success or 0 on timeout, but never negative
error codes. The current code incorrectly checks for negative
values, causing timeouts to be ignored and treated as success.

Check for a zero return value to correctly identify and
handle timeout events.

Fixes: 0cf7bef ("greybus: gb-beagleplay: Add firmware upload API")
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
Link: https://patch.msgid.link/20251121064027.571-1-vulab@iscas.ac.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: ISCAS-Vulab

drivers/greybus/gb-beagleplay.c

@@ -644,8 +644,8 @@ static int cc1352_bootloader_wait_for_ack(struct gb_beagleplay *bg)
 
 	ret = wait_for_completion_timeout(
 		&bg->fwl_ack_com, msecs_to_jiffies(CC1352_BOOTLOADER_TIMEOUT));
-	if (ret < 0)
-		return dev_err_probe(&bg->sd->dev, ret,
+	if (!ret)
+		return dev_err_probe(&bg->sd->dev, -ETIMEDOUT,
 				     "Failed to acquire ack semaphore");
 
 	switch (READ_ONCE(bg->fwl_ack)) {
@@ -683,8 +683,8 @@ static int cc1352_bootloader_get_status(struct gb_beagleplay *bg)
 	ret = wait_for_completion_timeout(
 		&bg->fwl_cmd_response_com,
 		msecs_to_jiffies(CC1352_BOOTLOADER_TIMEOUT));
-	if (ret < 0)
-		return dev_err_probe(&bg->sd->dev, ret,
+	if (!ret)
+		return dev_err_probe(&bg->sd->dev, -ETIMEDOUT,
 				     "Failed to acquire last status semaphore");
 
 	switch (READ_ONCE(bg->fwl_cmd_response)) {
@@ -768,8 +768,8 @@ static int cc1352_bootloader_crc32(struct gb_beagleplay *bg, u32 *crc32)
 	ret = wait_for_completion_timeout(
 		&bg->fwl_cmd_response_com,
 		msecs_to_jiffies(CC1352_BOOTLOADER_TIMEOUT));
-	if (ret < 0)
-		return dev_err_probe(&bg->sd->dev, ret,
+	if (!ret)
+		return dev_err_probe(&bg->sd->dev, -ETIMEDOUT,
 				     "Failed to acquire last status semaphore");
 
 	*crc32 = READ_ONCE(bg->fwl_cmd_response);