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

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>