... and take the error path if it fails.

Fixes the following W=1 kernel build warning(s):

 drivers/thunderbolt/dma_port.c: In function ‘dma_port_flash_write_block’:
 drivers/thunderbolt/dma_port.c:331:6: warning: variable ‘ret’ set but not used [-Wunused-but-set-variable]

Cc: Andreas Noever <andreas.noever@gmail.com>
Cc: Michael Jamet <redacted>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Yehezkel Bernat <YehezkelShB@gmail.com>
Cc: linux-usb@vger.kernel.org
Signed-off-by: Lee Jones <redacted>
---

v2: Different approach: actually handle the error.

 drivers/thunderbolt/dma_port.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/thunderbolt/dma_port.c b/drivers/thunderbolt/dma_port.c
index 847dd07a7b172..7288aaf01ae6a 100644
--- a/drivers/thunderbolt/dma_port.c
+++ b/drivers/thunderbolt/dma_port.c

@@ -335,6 +335,8 @@ static int dma_port_flash_write_block(struct tb_dma_port *dma, u32 address,
        /* Write the block to MAIL_DATA registers */
        ret = dma_port_write(sw->tb->ctl, buf, tb_route(sw), dma->port,
                            dma->base + MAIL_DATA, dwords, DMA_PORT_TIMEOUT);
+       if (ret)
+               return ret;
 
        in = MAIL_IN_CMD_FLASH_WRITE << MAIL_IN_CMD_SHIFT;