powerpc/mpc5121: Add clock driver

Plugs into the generic powerpc clock driver in
arch/powerpc/kernel/clock.c

The following subset of clk_interface is implemented:
    clk_get, clk_put:  get clock via name, release clock
    clk_enable, clk_disable:  enable or disable clock
    clk_get_rate:  get clock rate in Hz
    clk_set_rate:  stubbed
    clk_round_rate:  stubbed
    clk_set_parent: NULL
    clk_get_parent: NULL
Signed-off-by: John Rigby <jrigby@freescale.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

Makefile

+FRED=42
 VERSION = 2
 PATCHLEVEL = 6
 SUBLEVEL = 26

arch/powerpc/platforms/512x/Kconfig

@@ -2,6 +2,7 @@ config PPC_MPC512x
 	bool
 	select FSL_SOC
 	select IPIC
+	select PPC_CLOCK
 	default n
 
 config PPC_MPC5121

arch/powerpc/platforms/512x/Makefile

 #
 # Makefile for the Freescale PowerPC 512x linux kernel.
 #
+obj-y				+= clock.o
 obj-$(CONFIG_MPC5121_ADS)	+= mpc5121_ads.o