powerpc/85xx: Enhance get_sys_info() to check clocking mode

T1040 and it's variants provide "Single Oscillator Source" Reference Clock Mode.

In this mode, single onboard oscillator(DIFF_SYSCLK) can provide the reference clock
(100MHz) to the following PLLs:
• Platform PLL
• Core PLLs
• USB PLL
• DDR PLL, etc

The cfg_eng_use0 of porsr1 register identifies whether the SYSCLK (single-ended) or
DIFF_SYSCLK (differential) is selected as the clock input to the chip.

get_sys_info has been enhanced to add the diff_sysclk so that the
various drivers can be made aware of ths diff sysclk configuration and
act accordingly.

Other changes:
-single_src to ddr_refclk_sel, as it is use for checking ddr reference clock
-Removed the print of single_src from get_sys_info as this will be
-printed whenever somebody calls get_sys_info which is not appropriate.
-Add print of single_src in checkcpu as it is called only once during initialization

Signed-off-by: Poonam Aggrwal <poonam.aggrwal@freescale.com>
Signed-off-by: Priyanka Jain <Priyanka.Jain@freescale.com>
Signed-off-by: Vijay Rai <vijay.rai@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
diff --git a/arch/powerpc/cpu/mpc85xx/cpu.c b/arch/powerpc/cpu/mpc85xx/cpu.c
index 2c8126c..12e8e10 100644
--- a/arch/powerpc/cpu/mpc85xx/cpu.c
+++ b/arch/powerpc/cpu/mpc85xx/cpu.c
@@ -130,6 +130,11 @@
 
 	get_sys_info(&sysinfo);
 
+#ifdef CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
+	if (sysinfo.diff_sysclk == 1)
+		puts("Single Source Clock Configuration\n");
+#endif
+
 	puts("Clock Configuration:");
 	for_each_cpu(i, core, nr_cores, mask) {
 		if (!(i & 3))