ath10k: use firmware_request_nowarn() to load firmware

This reduces the unnecessary spew when trying to load optional firmware:
"Direct firmware load for ... failed with error -2"
Signed-off-by: Andres Rodriguez <andresx7@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

@@ -653,7 +653,7 @@ static const struct firmware *ath10k_fetch_fw_file(struct ath10k *ar,
 		dir = ".";
 
 	snprintf(filename, sizeof(filename), "%s/%s", dir, file);
-	ret = request_firmware(&fw, filename, ar->dev);
+	ret = firmware_request_nowarn(&fw, filename, ar->dev);
 	ath10k_dbg(ar, ATH10K_DBG_BOOT, "boot fw request '%s': %d\n",
 		   filename, ret);