ARM: dts: am3517-som: Fix WL127x Wifi interrupt

At the same time the AM3517 EVM was gaining WiFi support,
separate patches were introduced to move the interrupt
from HIGH to RISING.  Because they overlapped, this was not
done to the AM3517-EVM.  This patch fixes Kernel 4.19+

Fixes: 6bf5e341 ("ARM: dts: am3517-som: Add WL127x Wifi")

Signed-off-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>