ppc: Export __handle_mm_fault for MOL

When we did the handle_mm_fault cleanup and get_user_page() race fixes,
handle_mm_fault turned into an inline function that called the real
__handle_mm_fault() code.  The export needed for MOL on ppc wasn't
updated to match the new world order, though.

Turn it into a GPL export while at it, since this is all about internal
interfaces and MOL is GPL'd anwyay.

arch/ppc/kernel/ppc_ksyms.c

@@ -324,7 +324,7 @@ EXPORT_SYMBOL(__res);
 
 EXPORT_SYMBOL(next_mmu_context);
 EXPORT_SYMBOL(set_context);
-EXPORT_SYMBOL(handle_mm_fault); /* For MOL */
+EXPORT_SYMBOL_GPL(__handle_mm_fault); /* For MOL */
 EXPORT_SYMBOL(disarm_decr);
 #ifdef CONFIG_PPC_STD_MMU
 extern long mol_trampoline;