This makes the PPC40x lowmem large tlb mapping selectable via a cmdline
option.  This allows use of the normal page-sized mapping so that kernel
text can be read only if desired.
Signed-off-by: Josh Boyer <jwboyer@charter.net>
Signed-off-by: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>