fbcon: fix monochrome color value calculation

Commit 22af89aa0c0b4012a7431114a340efd3665a7617 ("fbcon: replace mono_col
macro with static inline") changed the order of operations for computing
monochrome color values. This generates 0xffff000f instead of 0x0000000f
for a 4 bit monochrome color, leading to image corruption if it is passed
to cfb_imageblit or other similar functions. Fix it up.

Cc: Harvey Harrison <[e-mail]>
Cc: "Antonino A. Daplas" <[e-mail]>
Cc: Krzysztof Helt <[e-mail]>
Cc: <[e-mail]> [2.6.26.x]
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/video/console/fbcon.h

···
 	__u32 max_len;
 	max_len = max(info->var.green.length, info->var.red.length);
 	max_len = max(info->var.blue.length, max_len);
-	return ~(0xfff << (max_len & 0xff));
+	return (~(0xfff << max_len)) & 0xff;
 }
 
 static inline int attr_col_ec(int shift, struct vc_data *vc,