mtd: nand: pxa3xx_nand: sync pxa3xx_nand_set_sdr_timing()

mtd: nand: pxa3xx_nand: sync pxa3xx_nand_set_sdr_timing()

Since the pxa3xx_nand driver was added there has been a discrepancy in
pxa3xx_nand_set_sdr_timing() around the setting of tWP_min and tRP_min.
This brings us into line with the current Linux code.

Signed-off-by: Chris Packham <[email protected]>
Signed-off-by: Ofer Heifetz <[email protected]>
Reviewed-by: Igal Liberman <[email protected]>
Cc: Stefan Roese <[email protected]>
Cc: Simon Glass <[email protected]>
Signed-off-by: Stefan Roese <[email protected]>