hw/9pfs: use O_NOFOLLOW for mapped readlink operation

With mapped security models like mapped-xattr and mapped-file, we save the
symlink target as file contents. Now if we ever expose a normal directory
with mapped security model and find real symlinks in export path, never
follow them and return proper error.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
ppc: do not register IABR SPR twice for 603e

IABR SPR is already registered in gen_spr_603(), called from init_proc_603E().

Signed-off-by: Hervé Poussineau <hpoussin@reactos.org>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>