thermal: rockchip: improve conversion error messages

These error messages don't give much information about what went wrong.
It would be nice, for one, to see what invalid temperature was being
requested when conversion fails. It's also good to return an error when
we can't handle a conversion properly.

While we're at it, fix the grammar too.
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>

drivers/thermal/rockchip_thermal.c

@@ -424,7 +424,8 @@ static u32 rk_tsadcv2_temp_to_code(struct chip_tsadc_table table,
 	}
 
 exit:
-	pr_err("Invalid the conversion, error=%d\n", error);
+	pr_err("%s: invalid temperature, temp=%d error=%d\n",
+	       __func__, temp, error);
 	return error;
 }
 
@@ -475,7 +476,8 @@ static int rk_tsadcv2_code_to_temp(struct chip_tsadc_table table, u32 code,
 		}
 		break;
 	default:
-		pr_err("Invalid the conversion table\n");
+		pr_err("%s: unknown table mode: %d\n", __func__, table.mode);
+		return -EINVAL;
 	}
 
 	/*