ARM: dts: stm32: remove useless interrupt-names property on stm32f429

Driver doesn't use interrupt's name to get it so remove it from
the node.

Signed-off-by: Benjamin Gaignard <[e-mail]>
Signed-off-by: Alexandre Torgue <[e-mail]>

arch/arm/boot/dts/stm32f429.dtsi

···
 			assigned-clock-parents = <&rcc 1 CLK_LSE>;
 			interrupt-parent = <&exti>;
 			interrupts = <17 1>;
-			interrupt-names = "alarm";
 			st,syscfg = <&pwrcfg 0x00 0x100>;
 			status = "disabled";
 		};