edd: add default mode CONFIG_EDD_OFF=n, override with edd={on,off}

Add a kernel parameter option to 'edd' to enable/disable BIOS Enhanced Disk
Drive Services.  CONFIG_EDD_OFF disables EDD while still compiling EDD into
the kernel.  Default behavior can be forced using 'edd=on' or 'edd=off' as
a kernel parameter.

[akpm@linux-foundation.org: fix kernel-parameters.txt]
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Matt Domsch <Matt_Domsch@dell.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 5afc21b2..3ce193f 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -627,8 +627,7 @@
 	eata=		[HW,SCSI]
 
 	edd=		[EDD]
-			Format: {"of[f]" | "sk[ipmbr]"}
-			See comment in arch/i386/boot/edd.S
+			Format: {"off" | "on" | "skip[mbr]"}
 
 	eisa_irq_edge=	[PARISC,HW]
 			See header of drivers/parisc/eisa.c.