powerpc/5xxx: Add common mpc5xxx_get_bus_frequency() function

So far, MPC512x used mpc512x_find_ips_freq() to get the bus frequency,
while MPC52xx used mpc52xx_find_ipb_freq().  Despite the different
clock names (IPS vs. IPB) the code was identical.

Use common code for both processor families.

Signed-off-by: Wolfgang Denk <wd@denx.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/serial/mpc52xx_uart.c b/drivers/serial/mpc52xx_uart.c
index b3feb61..abbd146 100644
--- a/drivers/serial/mpc52xx_uart.c
+++ b/drivers/serial/mpc52xx_uart.c
@@ -76,7 +76,6 @@
 #include <linux/of_platform.h>
 
 #include <asm/mpc52xx.h>
-#include <asm/mpc512x.h>
 #include <asm/mpc52xx_psc.h>
 
 #if defined(CONFIG_SERIAL_MPC52xx_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
@@ -254,7 +253,7 @@
 	 * but the generic serial code assumes 16
 	 * so return ipb freq / 2
 	 */
-	return mpc52xx_find_ipb_freq(p) / 2;
+	return mpc5xxx_get_bus_frequency(p) / 2;
 }
 
 static struct psc_ops mpc52xx_psc_ops = {
@@ -391,7 +390,7 @@
 
 static unsigned long mpc512x_getuartclk(void *p)
 {
-	return mpc512x_find_ips_freq(p);
+	return mpc5xxx_get_bus_frequency(p);
 }
 
 static struct psc_ops mpc512x_psc_ops = {