drm/tinydrm: Fix fbdev pixel format

Due to copy/paste error, the fbdev format was changed to 32bpp = XRGB8888
which is an emulated format for the RGB565 drivers. Revert to to using the
fallback which is dev->mode_config.preferred_depth for the drivers that
set it or 32bpp for those that don't (repaper, st7586).

Fixes: 3eba3922 ("drm/tinydrm: Drop using tinydrm_device")
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190410124345.25945-1-noralf@tronnes.org

drivers/gpu/drm/tinydrm/hx8357d.c

@@ -267,7 +267,7 @@ static int hx8357d_probe(struct spi_device *spi)
 
 	spi_set_drvdata(spi, drm);
 
-	drm_fbdev_generic_setup(drm, 32);
+	drm_fbdev_generic_setup(drm, 0);
 
 	return 0;
 }

drivers/gpu/drm/tinydrm/ili9225.c

@@ -433,7 +433,7 @@ static int ili9225_probe(struct spi_device *spi)
 
 	spi_set_drvdata(spi, drm);
 
-	drm_fbdev_generic_setup(drm, 32);
+	drm_fbdev_generic_setup(drm, 0);
 
 	return 0;
 }

drivers/gpu/drm/tinydrm/ili9341.c

@@ -229,7 +229,7 @@ static int ili9341_probe(struct spi_device *spi)
 
 	spi_set_drvdata(spi, drm);
 
-	drm_fbdev_generic_setup(drm, 32);
+	drm_fbdev_generic_setup(drm, 0);
 
 	return 0;
 }

drivers/gpu/drm/tinydrm/mi0283qt.c

@@ -242,7 +242,7 @@ static int mi0283qt_probe(struct spi_device *spi)
 
 	spi_set_drvdata(spi, drm);
 
-	drm_fbdev_generic_setup(drm, 32);
+	drm_fbdev_generic_setup(drm, 0);
 
 	return 0;
 }

drivers/gpu/drm/tinydrm/repaper.c

@@ -1131,7 +1131,7 @@ static int repaper_probe(struct spi_device *spi)
 
 	DRM_DEBUG_DRIVER("SPI speed: %uMHz\n", spi->max_speed_hz / 1000000);
 
-	drm_fbdev_generic_setup(drm, 32);
+	drm_fbdev_generic_setup(drm, 0);
 
 	return 0;
 }

drivers/gpu/drm/tinydrm/st7586.c

@@ -408,7 +408,7 @@ static int st7586_probe(struct spi_device *spi)
 	DRM_DEBUG_KMS("preferred_depth=%u, rotation = %u\n",
 		      drm->mode_config.preferred_depth, rotation);
 
-	drm_fbdev_generic_setup(drm, 32);
+	drm_fbdev_generic_setup(drm, 0);
 
 	return 0;
 }

drivers/gpu/drm/tinydrm/st7735r.c

@@ -207,7 +207,7 @@ static int st7735r_probe(struct spi_device *spi)
 
 	spi_set_drvdata(spi, drm);
 
-	drm_fbdev_generic_setup(drm, 32);
+	drm_fbdev_generic_setup(drm, 0);
 
 	return 0;
 }