serial: mxs-auart: Index is unsigned

Fix the following warning when building with W=1 option:

drivers/tty/serial/mxs-auart.c: In function 'mxs_auart_tx_chars':
drivers/tty/serial/mxs-auart.c:272:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index 9f63f8890a61..e55615eb34ad 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -253,7 +253,7 @@ static void mxs_auart_tx_chars(struct mxs_auart_port *s)
         struct circ_buf *xmit = &s->port.state->xmit;
 
         if (auart_dma_enabled(s)) {
-                int i = 0;
+                u32 i = 0;
                 int size;
                 void *buffer = s->tx_dma_buf;