driver/ddr/fsl: Add support for multiple DDR clocks

Controller number is passed for function calls to support individual
DDR clock, depending on SoC implementation. It is backward compatible
with exising platforms. Multiple clocks have been verifyed on LS2085A
emulator.

Signed-off-by: York Sun <yorksun@freescale.com>
diff --git a/drivers/ddr/fsl/ddr2_dimm_params.c b/drivers/ddr/fsl/ddr2_dimm_params.c
index d865df7..49cc1a0 100644
--- a/drivers/ddr/fsl/ddr2_dimm_params.c
+++ b/drivers/ddr/fsl/ddr2_dimm_params.c
@@ -211,10 +211,10 @@
  *
  * FIXME: use #define for the retvals
  */
-unsigned int
-ddr_compute_dimm_parameters(const ddr2_spd_eeprom_t *spd,
-			     dimm_params_t *pdimm,
-			     unsigned int dimm_number)
+unsigned int ddr_compute_dimm_parameters(const unsigned int ctrl_num,
+					 const ddr2_spd_eeprom_t *spd,
+					 dimm_params_t *pdimm,
+					 unsigned int dimm_number)
 {
 	unsigned int retval;
 
@@ -310,8 +310,8 @@
 					  & ~(1 << pdimm->caslat_x_minus_1));
 
 	/* Compute CAS latencies below that defined by SPD */
-	pdimm->caslat_lowest_derated
-		= compute_derated_DDR2_CAS_latency(get_memory_clk_period_ps());
+	pdimm->caslat_lowest_derated = compute_derated_DDR2_CAS_latency(
+					get_memory_clk_period_ps(ctrl_num));
 
 	/* Compute timing parameters */
 	pdimm->trcd_ps = spd->trcd * 250;