ARM: dts: microchip: sam9x60ek: rename spi-cs-setup-ns property to spi-cs-setup-delay-ns

ARM: dts: microchip: sam9x60ek: rename spi-cs-setup-ns property to spi-cs-setup-delay-ns

The naming scheme for delay properties includes "delay" in the name,
so renaming spi-cs-setup-ns property to spi-cs-setup-delay-ns.

Fixes: 2c0a1faa4da5 ("ARM: dts: at91: sam9x60ek: Set sst26vf064b SPI NOR flash at its maximum frequency")
Signed-off-by: Manikandan Muralidharan <manikandan.m@microchip.com>
Reviewed-by: Alexander Dahl <ada@thorsis.com>
Link: https://lore.kernel.org/r/20250521054309.361894-1-manikandan.m@microchip.com
Signed-off-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>