ppc: Move mpc5xxx clocks to arch_global_data

Move ipb_clk and pci_clk into arch_global_data and tidy up.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/input/ps2ser.c b/drivers/input/ps2ser.c
index a655a16..bcbe52a 100644
--- a/drivers/input/ps2ser.c
+++ b/drivers/input/ps2ser.c
@@ -80,7 +80,7 @@
 
 	/* select clock sources */
 	psc->psc_clock_select = 0;
-	baseclk = (gd->ipb_clk + 16) / 32;
+	baseclk = (gd->arch.ipb_clk + 16) / 32;
 
 	/* switch to UART mode */
 	psc->sicr = 0;