doc: typo in Documentation/filesystems/nfsroot.txt

Add a missing word to the explanation of the purpose of the zdisk and
bzdisk make targets.
Signed-off-by: Shane McDonald <mcdonald.shane@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/filesystems/nfsroot.txt

@@ -169,7 +169,7 @@ They depend on various facilities being available:
 3.1)  Booting from a floppy using syslinux
 
 	When building kernels, an easy way to create a boot floppy that uses
-	syslinux is to use the zdisk or bzdisk make targets which use
+	syslinux is to use the zdisk or bzdisk make targets which use zimage
       	and bzimage images respectively. Both targets accept the
      	FDARGS parameter which can be used to set the kernel command line.