fix: panel-cwu50 timing fix from Rex's kernel - native 720x1280 mode

Swap H/V display mode to native panel resolution (720x1280) instead of
rotated (1280x720). The DRM/KMS pipeline handles rotation via connector
orientation property. Setting wrong horizontal resolution caused DSI
controller to send extra pixels per line, resulting in horizontal
repetition.

Add DCS-based panel detection in init_sequence2 as supplemental check.

Based on ak-rex/ClockworkPi-linux rpi-6.12.y branch panel-cwu50.c.

Replaces old 0008 patches (DSI_INIT0, BURST removal) that didn't fix
the issue.

patches/0008-panel-cwu50-rex-timing-fix.patch

@@ -0,0 +1,45 @@
+--- a/drivers/gpu/drm/panel/panel-cwu50.c
++++ b/drivers/gpu/drm/panel/panel-cwu50.c
+@@ -27,12 +27,12 @@ static const struct drm_display_mode default_mode = {
+ 	.clock = 61020,
+-	.hdisplay = 1280,
+-	.hsync_start = 1280 + 8,
+-	.hsync_end = 1280 + 8 + 2,
+-	.htotal = 1280 + 8 + 2 + 16,
+-	.vdisplay = 720,
+-	.vsync_start = 720 + 30,
+-	.vsync_end = 720 + 30 + 15,
+-	.vtotal = 720 + 30 + 15 + 15,
++	.hdisplay = 720,
++	.hsync_start = 720 + 30,
++	.hsync_end = 720 + 30 + 15,
++	.htotal = 720 + 30 + 15 + 15,
++	.vdisplay = 1280,
++	.vsync_start = 1280 + 8,
++	.vsync_end = 1280 + 8 + 2,
++	.vtotal = 1280 + 8 + 2 + 16,
+ };
+ 
+ static inline struct cwu50 *panel_to_cwu50(struct drm_panel *panel)
+@@ -586,7 +586,8 @@ static int cwu50_init_sequence2(struct cwu50 *ctx)
+ {
+ 	struct mipi_dsi_device *dsi = to_mipi_dsi_device(ctx->dev);
+-	int err;
++	int err;
++	u8 buf[4];
+ 
+ 	dcs_write_seq(0xE0,0x00);
+ 
+@@ -633,6 +634,12 @@ static int cwu50_init_sequence2(struct cwu50 *ctx)
+ 
+ 	dcs_write_seq(0x11);// SLPOUT
+ 	msleep (200);
++	dcs_write_seq(0xE0,0x00);
++	mipi_dsi_dcs_read(dsi, 0x04, buf, 3);
++
++	if(buf[0] == 0x39) ctx->is_new_panel = 1;
++
++	dcs_write_seq(0xE0,0x00);
+ 
+ 	dcs_write_seq(0x29);// DSiPON
+ 	msleep (100);