drm/bridge: anx7625: Propagate errors from sp_tx_rst_aux()

The return value of sp_tx_rst_aux() is not propagated, which means
both compiler warnings and potential errors not being handled.

Fixes: 8bdfc5da ("drm/bridge: anx7625: Add anx7625 MIPI DSI/DPI to DP")
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210818171318.1848272-1-robert.foss@linaro.org

drivers/gpu/drm/bridge/analogix/anx7625.c

@@ -720,7 +720,7 @@ static int edid_read(struct anx7625_data *ctx,
 		ret = sp_tx_aux_rd(ctx, 0xf1);
 
 		if (ret) {
-			sp_tx_rst_aux(ctx);
+			ret = sp_tx_rst_aux(ctx);
 			DRM_DEV_DEBUG_DRIVER(dev, "edid read fail, reset!\n");
 		} else {
 			ret = anx7625_reg_block_read(ctx, ctx->i2c.rx_p0_client,
@@ -735,7 +735,7 @@ static int edid_read(struct anx7625_data *ctx,
 	if (cnt > EDID_TRY_CNT)
 		return -EIO;
 
-	return 0;
+	return ret;
 }
 
 static int segments_edid_read(struct anx7625_data *ctx,
@@ -785,7 +785,7 @@ static int segments_edid_read(struct anx7625_data *ctx,
 	if (cnt > EDID_TRY_CNT)
 		return -EIO;
 
-	return 0;
+	return ret;
 }
 
 static int sp_tx_edid_read(struct anx7625_data *ctx,
@@ -887,7 +887,11 @@ static int sp_tx_edid_read(struct anx7625_data *ctx,
 	}
 
 	/* Reset aux channel */
-	sp_tx_rst_aux(ctx);
+	ret = sp_tx_rst_aux(ctx);
+	if (ret < 0) {
+		DRM_DEV_ERROR(dev, "Failed to reset aux channel!\n");
+		return ret;
+	}
 
 	return (blocks_num + 1);
 }