[MIPS] Export local_flush_data_cache_page for sake of IDE.

On a CPU with aliases the IDE core needs to flush caches in the special
IDE variants of insw, insl etc.  If IDE support is built as a module this
will only work if local_flush_data_cache_page happens is exported as a
module.

As per policy export local_flush_data_cache_page as GPL symbol only.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/mm/cache.c

@@ -32,6 +32,7 @@ void (*local_flush_data_cache_page)(void * addr);
 void (*flush_data_cache_page)(unsigned long addr);
 void (*flush_icache_all)(void);
 
+EXPORT_SYMBOL_GPL(local_flush_data_cache_page);
 EXPORT_SYMBOL(flush_data_cache_page);
 
 #ifdef CONFIG_DMA_NONCOHERENT