ARM: dts: at91: sama5d4_xplained: fix pinctrl phandle name

Pinctrl phandle is for spi1 so rename it to reflect this.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20220331141323.194355-1-claudiu.beznea@microchip.com