ARM: dts: am437x: align ti,pindir-d0-out-d1-in property with dt-shema

ti,pindir-d0-out-d1-in property is expected to be of type boolean.
Therefore, fix the property accordingly.

Fixes: b0b03951 ("ARM: dts: am43x-epos-evm: set data pin directions for spi0 and spi1")
Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>