[POWERPC] Remove unneeded page_is_ram export

arch/powerpc/mm/mem.c exports page_is_ram, which is not used anywhere
that could be modular.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index c4bcd75..1a6e08f 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -80,7 +80,6 @@
 	return 0;
 #endif
 }
-EXPORT_SYMBOL(page_is_ram);
 
 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 			      unsigned long size, pgprot_t vma_prot)