remove frv usage of flush_tlb_pgtables()

frv is the last user in the tree of that dubious hook, and it's my
understanding that it's not even needed.  It's only called by memory.c
free_pgd_range() which is always called within an mmu_gather, and
tlb_flush() on frv will do a flush_tlb_mm(), which from my reading of the
code, seems to do what flush_tlb_ptables() does, which is to clear the
cached PGE.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-By: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/asm-frv/tlbflush.h

@@ -57,8 +57,7 @@ do {								\
 #define __flush_tlb_global()			flush_tlb_all()
 #define flush_tlb()				flush_tlb_all()
 #define flush_tlb_kernel_range(start, end)	flush_tlb_all()
-#define flush_tlb_pgtables(mm,start,end) \
-	asm volatile("movgs %0,scr0 ! movgs %0,scr1" :: "r"(ULONG_MAX) : "memory");
+#define flush_tlb_pgtables(mm,start,end)	do { } while(0)
 
 #else