drm/vc4: crtc: Move assigned_channel to a variable

We access multiple times the vc4_crtc_state->assigned_channel variable
in the vc4_crtc_get_scanout_position() function, so let's store it in a
local variable.

Signed-off-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240621152055.4180873-14-dave.stevenson@raspberrypi.com
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>

drivers/gpu/drm/vc4/vc4_crtc.c

@@ -105,6 +105,7 @@ static bool vc4_crtc_get_scanout_position(struct drm_crtc *crtc,
 	struct vc4_hvs *hvs = vc4->hvs;
 	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
 	struct vc4_crtc_state *vc4_crtc_state = to_vc4_crtc_state(crtc->state);
+	unsigned int channel = vc4_crtc_state->assigned_channel;
 	unsigned int cob_size;
 	u32 val;
 	int fifo_lines;
@@ -121,7 +122,7 @@ static bool vc4_crtc_get_scanout_position(struct drm_crtc *crtc,
 	 * Read vertical scanline which is currently composed for our
 	 * pixelvalve by the HVS, and also the scaler status.
 	 */
-	val = HVS_READ(SCALER_DISPSTATX(vc4_crtc_state->assigned_channel));
+	val = HVS_READ(SCALER_DISPSTATX(channel));
 
 	/* Get optional system timestamp after query. */
 	if (etime)
@@ -137,11 +138,11 @@ static bool vc4_crtc_get_scanout_position(struct drm_crtc *crtc,
 		*vpos /= 2;
 
 		/* Use hpos to correct for field offset in interlaced mode. */
-		if (vc4_hvs_get_fifo_frame_count(hvs, vc4_crtc_state->assigned_channel) % 2)
+		if (vc4_hvs_get_fifo_frame_count(hvs, channel) % 2)
 			*hpos += mode->crtc_htotal / 2;
 	}
 
-	cob_size = vc4_crtc_get_cob_allocation(vc4, vc4_crtc_state->assigned_channel);
+	cob_size = vc4_crtc_get_cob_allocation(vc4, channel);
 	/* This is the offset we need for translating hvs -> pv scanout pos. */
 	fifo_lines = cob_size / mode->crtc_hdisplay;