powerpc: Define/use HUGETLB_NEED_PRELOAD insead of complicated #if

Define HUGETLB_NEED_PRELOAD in mmu-book3e.h for CONFIG_PPC64 instead
of having a much more complicated #if block.  This is easier to read
and maintain.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/mmu-book3e.h

@@ -258,6 +258,13 @@ extern int mmu_vmemmap_psize;
 
 #ifdef CONFIG_PPC64
 extern unsigned long linear_map_top;
+
+/*
+ * 64-bit booke platforms don't load the tlb in the tlb miss handler code.
+ * HUGETLB_NEED_PRELOAD handles this - it causes huge_ptep_set_access_flags to
+ * return 1, indicating that the tlb requires preloading.
+ */
+#define HUGETLB_NEED_PRELOAD
 #endif
 
 #endif /* !__ASSEMBLY__ */