ARM: dts: am335x: Fix the interrupt name of TPS65217

Use 'interrupt-names' for getting the charger interrupt number.

Fixes: 1934e89a ("ARM: dts: am335x: Add the charger interrupt")
Signed-off-by: Milo Kim <woogyom.kim@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>