mtd: nand: Add a few more timings to nand_sdr_timings

Add the tR_max, tBERS_max, tPROG_max and tCCS_min timings to the
nand_sdr_timings struct.
Assign default/safe values for the statically defined timings, and
extract them from the ONFI parameter table if the NAND is ONFI
compliant.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Tested-by: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>