drm/tinydrm: Replace dev_error with DRM_DEV_ERROR

Convert instances of dev_error to DRM_DEV_ERROR as we have
DRM_DEV_ERROR variants of drm print macros.

Signed-off-by: Harsha Sharma <harshasharmaiitr@gmail.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20171006221738.30200-1-harshasharmaiitr@gmail.com
diff --git a/drivers/gpu/drm/tinydrm/st7586.c b/drivers/gpu/drm/tinydrm/st7586.c
index da9c0d8..0a2c60d 100644
--- a/drivers/gpu/drm/tinydrm/st7586.c
+++ b/drivers/gpu/drm/tinydrm/st7586.c
@@ -188,7 +188,7 @@ static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
 	mipi_dbi_hw_reset(mipi);
 	ret = mipi_dbi_command(mipi, ST7586_AUTO_READ_CTRL, 0x9f);
 	if (ret) {
-		dev_err(dev, "Error sending command %d\n", ret);
+		DRM_DEV_ERROR(dev, "Error sending command %d\n", ret);
 		return;
 	}
 
@@ -355,13 +355,13 @@ static int st7586_probe(struct spi_device *spi)
 
 	mipi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
 	if (IS_ERR(mipi->reset)) {
-		dev_err(dev, "Failed to get gpio 'reset'\n");
+		DRM_DEV_ERROR(dev, "Failed to get gpio 'reset'\n");
 		return PTR_ERR(mipi->reset);
 	}
 
 	a0 = devm_gpiod_get(dev, "a0", GPIOD_OUT_LOW);
 	if (IS_ERR(a0)) {
-		dev_err(dev, "Failed to get gpio 'a0'\n");
+		DRM_DEV_ERROR(dev, "Failed to get gpio 'a0'\n");
 		return PTR_ERR(a0);
 	}