drm/sun4i: vi_scaler: Update DE33 base calculation

Now that channel base calculation is straightforward, let's update VI
scaler base calculation to be simpler. At the same time, also introduce
macro to avoid magic numbers.

Note, reason why current magic value and new macro value isn't the same
is because sun8i_channel_base() already introduces offset to channel
registers. Previous value is just the difference to VI scaler registers.
However, new code calculates scaler base from channel base. This is also
easier to understand when looking into BSP driver. Macro value can be
easily found whereas old diff value was not.

Reviewed-by: Chen-Yu Tsai <wens@kernel.org>
Tested-by: Ryan Walklin <ryan@testtoast.com>
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://patch.msgid.link/20251104180942.61538-24-jernej.skrabec@gmail.com
Signed-off-by: Chen-Yu Tsai <wens@kernel.org>

Author: jernejsk

drivers/gpu/drm/sun4i/sun8i_vi_scaler.c

@@ -836,7 +836,8 @@ static const u32 bicubic4coefftab32[480] = {
 static u32 sun8i_vi_scaler_base(struct sun8i_mixer *mixer, int channel)
 {
 	if (mixer->cfg->de_type == SUN8I_MIXER_DE33)
-		return sun8i_channel_base(mixer, channel) + 0x3000;
+		return DE33_VI_SCALER_UNIT_BASE +
+		       DE33_CH_SIZE * channel;
 	else if (mixer->cfg->de_type == SUN8I_MIXER_DE3)
 		return DE3_VI_SCALER_UNIT_BASE +
 		       DE3_VI_SCALER_UNIT_SIZE * channel;

drivers/gpu/drm/sun4i/sun8i_vi_scaler.h

@@ -18,6 +18,8 @@
 #define DE3_VI_SCALER_UNIT_BASE 0x20000
 #define DE3_VI_SCALER_UNIT_SIZE 0x08000
 
+#define DE33_VI_SCALER_UNIT_BASE 0x4000
+
 /* this two macros assumes 16 fractional bits which is standard in DRM */
 #define SUN8I_VI_SCALER_SCALE_MIN		1
 #define SUN8I_VI_SCALER_SCALE_MAX		((1UL << 20) - 1)