ARM: dts: at91: usb_a9263: fix GPIO for Dataflash chip select

Dataflash did not work on my board. After checking schematics and using
the proper GPIO, it works now. Also, make it active low to avoid:

flash@0 enforce active low on GPIO handle

Fixes: 2432d201 ("ARM: at91: dt: usb-a9263: add dataflash support")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20250404112742.67416-2-wsa+renesas@sang-engineering.com


Signed-off-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>