ARM: dts: am57xx-idk: Add Industrial input support

The SN65HVS882 is available on both the AM572x and AM571x IDKs and is
attached to SPI1. Input is attached to the I/O header. The load trigger
is attached to GPIO3_19 on the AM572x IDK.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>