powerpc: Remove __ilog2_u64 and ffs4 from bitops

Remove __ilog2_u64 and ffs4 from powerpc bitops to align with the
kernel implementation.

Use the generic __ffs64 instead of a custom powerpc implementation.

Cc: York Sun <yorksun@freescale.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Jagan Teki <jteki@openedev.com>
diff --git a/arch/powerpc/cpu/mpc85xx/tlb.c b/arch/powerpc/cpu/mpc85xx/tlb.c
index 8e0508f..cf31eb2 100644
--- a/arch/powerpc/cpu/mpc85xx/tlb.c
+++ b/arch/powerpc/cpu/mpc85xx/tlb.c
@@ -14,6 +14,8 @@
 #include <addr_map.h>
 #endif
 
+#include <linux/log2.h>
+
 DECLARE_GLOBAL_DATA_PTR;
 
 void invalidate_tlb(u8 tlb)