ath10k: remove the warning of sdio not full support

Recently, it has the basic feature of sdio tested success, so remove
it.

Tested with QCA6174 SDIO with firmware
WLAN.RMH.4.4.1-00017-QCARMSWP-1.
Signed-off-by: Wen Gong <wgong@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/ath10k/sdio.c

@@ -2086,9 +2086,6 @@ static int ath10k_sdio_probe(struct sdio_func *func,
 		goto err_free_wq;
 	}
 
-	/* TODO: remove this once SDIO support is fully implemented */
-	ath10k_warn(ar, "WARNING: ath10k SDIO support is work-in-progress, problems may arise!\n");
-
 	return 0;
 
 err_free_wq: