dt: socfpga: Replace num-chipselect with num-cs

dt: socfpga: Replace num-chipselect with num-cs

This optional DT property is called 'num-cs', so repair the misnomers.

Signed-off-by: Marek Vasut <[email protected]>
Cc: Chin Liang See <[email protected]>
Cc: Dinh Nguyen <[email protected]>
Cc: Pavel Machek <[email protected]>
Cc: Stefan Roese <[email protected]>
Cc: Vince Bridgers <[email protected]>
Acked-by: Pavel Machek <[email protected]>
Reviewed-by: Jagannadha Sutradharudu Teki <[email protected]>