sh: Use DECLARE_EXPORT() for mcount symbol export.

The function prototype for mcount is not defined if we are not building
with ftrace support enabled, so use DECLARE_EXPORT() to stub one in.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

arch/sh/kernel/sh_ksyms_32.c

@@ -107,7 +107,7 @@ EXPORT_SYMBOL(clear_user_page);
 #endif
 
 #ifdef CONFIG_MCOUNT
-EXPORT_SYMBOL(mcount);
+DECLARE_EXPORT(mcount);
 #endif
 EXPORT_SYMBOL(csum_partial);
 EXPORT_SYMBOL(csum_partial_copy_generic);