drm/vc4: hdmi: Correct HDMI timing registers for interlaced modes

For interlaced modes the timings were not being correctly
programmed into the HDMI block, so correct them.

Fixes: 83239891 ("drm/vc4: hdmi: Support the BCM2711 HDMI controllers")
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://lore.kernel.org/r/20220613144800.326124-33-maxime@cerno.techSigned-off-by: Maxime Ripard <maxime@cerno.tech>

drivers/gpu/drm/vc4/vc4_hdmi.c

@@ -1036,13 +1036,13 @@ static void vc5_hdmi_set_timings(struct vc4_hdmi *vc4_hdmi,
 		     VC4_SET_FIELD(mode->crtc_vsync_start - mode->crtc_vdisplay,
 				   VC5_HDMI_VERTA_VFP) |
 		     VC4_SET_FIELD(mode->crtc_vdisplay, VC5_HDMI_VERTA_VAL));
-	u32 vertb = (VC4_SET_FIELD(0, VC5_HDMI_VERTB_VSPO) |
-		     VC4_SET_FIELD(mode->crtc_vtotal - mode->crtc_vsync_end +
-				   interlaced,
+	u32 vertb = (VC4_SET_FIELD(mode->htotal >> (2 - pixel_rep),
+				   VC5_HDMI_VERTB_VSPO) |
+		     VC4_SET_FIELD(mode->crtc_vtotal - mode->crtc_vsync_end,
 				   VC4_HDMI_VERTB_VBP));
 	u32 vertb_even = (VC4_SET_FIELD(0, VC5_HDMI_VERTB_VSPO) |
 			  VC4_SET_FIELD(mode->crtc_vtotal -
-					mode->crtc_vsync_end,
+					mode->crtc_vsync_end - interlaced,
 					VC4_HDMI_VERTB_VBP));
 	unsigned long flags;
 	unsigned char gcp;