Configure busturnaround, cycle2cycledelay, waitmonitoringtime,
clkactivationtime in gpmc_cs_set_timings(). This is done so
that boards can configure these parameters of gpmc in Kernel
instead of relying on bootloader. Also configure bool type
timings like extradelay.

This needed change to the existing users that were configuring
clk activation time and extra delay by directly writing to
registers. Thanks to Tony for making me aware of users of clk
activation and being kind enough to test the modified one.
Signed-off-by: Afzal Mohammed <afzal@ti.com>