arm: dts: k3-am654: remove duplicate timer

timer1 is really just the mcu_timer0 node redefined for the WKUP SPL.
Remove the timer1 and replace it with the mcu_timer0 from the Linux
device tree we imported into U-Boot.

Tested-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Bryan Brattlof <bb@ti.com>
Reviewed-by: Nishanth Menon <nm@ti.com>