arm64: dts: ti: k3-am68-sk-som: Change timer nodes status to reserved

arm64: dts: ti: k3-am68-sk-som: Change timer nodes status to reserved

The remoteproc firmware like of R5F and DSPs in the MAIN voltage domain
use timers. Therefore, change the status of the timer nodes to
"reserved" to avoid any clash. Usage is described as below:

	+===================+=============+
	|  Remoteproc node  | Timer Node  |
	+===================+=============+
	| main_r5fss0_core0 | main_timer2 |
	+-------------------+-------------+
	| main_r5fss0_core1 | main_timer3 |
	+-------------------+-------------+
	| main_r5fss1_core0 | main_timer4 |
	+-------------------+-------------+
	| main_r5fss1_core1 | main_timer5 |
	+-------------------+-------------+
	| c71_0             | main_timer0 |
	+-------------------+-------------+
	| c71_1             | main_timer1 |
	+-------------------+-------------+

Signed-off-by: Beleswar Padhi <b-padhi@ti.com>
Link: https://lore.kernel.org/r/20240826104821.1516344-6-b-padhi@ti.com
Signed-off-by: Nishanth Menon <nm@ti.com>