sh: Define _ebss for uClinux MTD map driver.

The uClinux MTD device uses _ebss, add the symbol and corresponding
export.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/include/asm-sh/sections.h b/include/asm-sh/sections.h
index 2a696b8..bd9cbc9 100644
--- a/include/asm-sh/sections.h
+++ b/include/asm-sh/sections.h
@@ -4,6 +4,7 @@
 #include <asm-generic/sections.h>
 
 extern long __machvec_start, __machvec_end;
+extern char _ebss[];
 
 #endif /* __ASM_SH_SECTIONS_H */