libertas: remove redundant initialization of variable ret

The variable ret is being initialized with a value that is never read
and it is being updated later with a new value.  The initialization is
redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210128162202.642848-1-colin.king@canonical.com

drivers/net/wireless/marvell/libertas/if_sdio.c

@@ -981,7 +981,7 @@ static int if_sdio_host_to_card(struct lbs_private *priv,
 
 static int if_sdio_enter_deep_sleep(struct lbs_private *priv)
 {
-	int ret = -1;
+	int ret;
 	struct cmd_header cmd;
 
 	memset(&cmd, 0, sizeof(cmd));