ddr: altera: Configuring SDRAM extra cycles timing parameters

ddr: altera: Configuring SDRAM extra cycles timing parameters

To enable configuration of sdr.ctrlcfg.extratime1 register which enable
extra clocks for read to write command timing. This is critical to
ensure successful LPDDR2 interface

Signed-off-by: Chin Liang See <clsee@altera.com>
Cc: Marek Vasut <marex@denx.de>
Cc: Dinh Nguyen <dinguyen@opensource.altera.com>