drm/amd/display: Use pitch when calculating size to cache in MALL

[Description]
Use pitch when calculating size to cache in MALL

Reviewed-by: Samson Tam <[e-mail]>
Acked-by: Brian Chang <[e-mail]>
Signed-off-by: Alvin Lee <[e-mail]>
Tested-by: Daniel Wheeler <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource_helpers.c

···
 		if (pipe->stream && pipe->plane_state && !pipe->top_pipe &&
 				pipe->stream->mall_stream_config.type == SUBVP_PHANTOM) {
 			bytes_per_pixel = pipe->plane_state->format >= SURFACE_PIXEL_FORMAT_GRPH_ARGB16161616 ? 8 : 4;
-			mall_region_pixels = pipe->stream->timing.h_addressable * pipe->stream->timing.v_addressable;
+			mall_region_pixels = pipe->plane_state->plane_size.surface_pitch * pipe->stream->timing.v_addressable;
 
 			// For bytes required in MALL, calculate based on number of MBlks required
 			num_mblks = (mall_region_pixels * bytes_per_pixel +