ARM: dts: Drop bogus CLKSEL for timer12 on dra7

There is no CLKSEL for timer12 on dra7 unlike for timer1. This
causes issues on booting the device that Tomi noticed if
DEBUG_SLAB is enabled and the clkctrl clock does not properly
handle non-existing clock. Let's drop the bogus CLKSEL clock,
the clkctrl clock handling gets fixed separately.

Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: Tero Kristo <t-kristo@ti.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Tested-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Tested-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Fixes: 4ed0dfe3 ("ARM: dts: dra7: Move l4 child devices to probe them with ti-sysc")
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/dra7-l4.dtsi

@@ -4450,8 +4450,6 @@ target-module@0 {			/* 0x4ae20000, ap 19 08.0 */
 			timer12: timer@0 {
 				compatible = "ti,omap5430-timer";
 				reg = <0x0 0x80>;
-				clocks = <&wkupaon_clkctrl DRA7_WKUPAON_TIMER12_CLKCTRL 24>;
-				clock-names = "fck";
 				interrupts = <GIC_SPI 90 IRQ_TYPE_LEVEL_HIGH>;
 				ti,timer-alwon;
 				ti,timer-secure;