cirrusfb: add Laguna additional overflow register

Add additional overflow register setting for Laguna chips.

Also, simplify some code in the cirrusfb_pan_display() and
cirrusfb_blank().

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/video/cirrus.h b/include/video/cirrus.h
index b2776b6..a1b7985 100644
--- a/include/video/cirrus.h
+++ b/include/video/cirrus.h
@@ -71,6 +71,7 @@
 #define CL_CRT1B	0x1b	/* Extended Display Controls */
 #define CL_CRT1C	0x1c	/* Sync adjust and genlock register */
 #define CL_CRT1D	0x1d	/* Overlay Extended Control register */
+#define CL_CRT1E	0x1e	/* Another overflow register */
 #define CL_CRT25	0x25	/* Part Status Register */
 #define CL_CRT27	0x27	/* ID Register */
 #define CL_CRT51	0x51	/* P4 disable "flicker fixer" */