board/sama5d3xek: add operation clock options

Bus clocks:132MHz/166MHz, and corresponding Processor clocks

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
DDR2-SRAM: add timer configurations support for 166MHz

This parameters will be improved after the HW team finish the testing.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
defconfig/at91sama5d3xek: update the default configuration files

Due to adding some PCK and MCK options and LINK Address changing

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>