sh: Preparation for uncached jumps through PMB.

Presently most of the 29-bit physical parts do P1/P2 segmentation
with a 1:1 cached/uncached mapping, jumping between the two to
control the caching behaviour. This provides the basic infrastructure
to maintain this behaviour on 32-bit physical parts that don't map
P1/P2 at all, using a shiny new linker section and corresponding
fixmap entry.

Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/include/asm-sh/system.h b/include/asm-sh/system.h
index 969f3d4..9bda8d0 100644
--- a/include/asm-sh/system.h
+++ b/include/asm-sh/system.h
@@ -144,6 +144,8 @@
 #define instruction_size(insn)	(4)
 #endif
 
+extern unsigned long cached_to_uncached;
+
 /* XXX
  * disable hlt during certain critical i/o operations
  */