fix fs/nfs/nfsroot.c compilation

This fixes the following compile error caused by commit
f9247273 ("UFS: add const to parser
token table"):

    CC      fs/nfs/nfsroot.o
  /home/bunk/linux/kernel-2.6/git/linux-2.6/fs/nfs/nfsroot.c:130: error: tokens causes a section type conflict
  make[3]: *** [fs/nfs/nfsroot.o] Error 1
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fs/nfs/nfsroot.c

@@ -127,7 +127,7 @@ enum {
 	Opt_err
 };
 
-static match_table_t __initdata tokens = {
+static match_table_t __initconst tokens = {
 	{Opt_port, "port=%u"},
 	{Opt_rsize, "rsize=%u"},
 	{Opt_wsize, "wsize=%u"},