habanalabs: return error when failing to read/write i2c

The driver can't read/write from i2c if the device is in reset or
disabled. Therefore, return -EBUSY in those cases instead of 0.

This change also fixes a smatch warning about uninitialized variable.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/habanalabs/debugfs.c

@@ -25,7 +25,7 @@ static int hl_debugfs_i2c_read(struct hl_device *hdev, u8 i2c_bus, u8 i2c_addr,
 	int rc;
 
 	if (hl_device_disabled_or_in_reset(hdev))
-		return 0;
+		return -EBUSY;
 
 	memset(&pkt, 0, sizeof(pkt));
 
@@ -50,7 +50,7 @@ static int hl_debugfs_i2c_write(struct hl_device *hdev, u8 i2c_bus, u8 i2c_addr,
 	int rc;
 
 	if (hl_device_disabled_or_in_reset(hdev))
-		return 0;
+		return -EBUSY;
 
 	memset(&pkt, 0, sizeof(pkt));