atmel_lcdfb: add board parameter specify framebuffer memory size

Specify how much physically continuous, DMA capable memory will be
allocated at driver initialization time.  This allow to create framebuffer
device with larger virtual resolution.  Combine with y-panning this can be
used to implement double buffering acceleration method.

Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl>
Acked-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Acked-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/video/atmel_lcdc.h b/include/video/atmel_lcdc.h
index 613173b..920c4e9 100644
--- a/include/video/atmel_lcdc.h
+++ b/include/video/atmel_lcdc.h
@@ -41,6 +41,7 @@
 	struct work_struct	task;
 
 	unsigned int		guard_time;
+	unsigned int 		smem_len;
 	struct platform_device	*pdev;
 	struct clk		*bus_clk;
 	struct clk		*lcdc_clk;