[PATCH] powermac backlight fixes

Fix a erroneous calculation of the legacy brightness values as reported by
Paul Collins.  Additionally, it moves the calculation of the negative value
in the radeonfb driver after the value check.

Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Paul Collins <paul@briny.ondioline.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/video/aty/radeon_backlight.c b/drivers/video/aty/radeon_backlight.c
index 7de66b8..1755ddd 100644
--- a/drivers/video/aty/radeon_backlight.c
+++ b/drivers/video/aty/radeon_backlight.c
@@ -40,14 +40,14 @@
 
 	mutex_unlock(&info->bl_mutex);
 
-	if (pdata->negative)
-		rlevel = MAX_RADEON_LEVEL - rlevel;
-
 	if (rlevel < 0)
 		rlevel = 0;
 	else if (rlevel > MAX_RADEON_LEVEL)
 		rlevel = MAX_RADEON_LEVEL;
 
+	if (pdata->negative)
+		rlevel = MAX_RADEON_LEVEL - rlevel;
+
 	return rlevel;
 }