ppc/p4080: Handle timebase enabling and frequency reporting

On CoreNet style platforms the timebase frequency is the bus frequency
defined by 16 (on PQ3 it is divide by 8).  Also on the CoreNet platforms
the core not longer controls the enabling of the timebase.  We now need
to enable the boot core's timebase via CCSR register writes.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/cpu/mpc85xx/cpu.c b/cpu/mpc85xx/cpu.c
index bdd9ee4..25c0416 100644
--- a/cpu/mpc85xx/cpu.c
+++ b/cpu/mpc85xx/cpu.c
@@ -184,7 +184,11 @@
  */
 unsigned long get_tbclk (void)
 {
+#ifdef CONFIG_FSL_CORENET
+	return (gd->bus_clk + 8) / 16;
+#else
 	return (gd->bus_clk + 4UL)/8UL;
+#endif
 }