arm: omap: sdram-nokia: prepare for new memory timings

Rename the current timings to indicate they're for 166 MHz. Based on
patches by Eduardo Valentin and Juha Keski-Saari.

Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Cc: Eduardo Valentin <eduardo.valentin@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>