arch: arm: mach-k3: am642_init: Probe ESM nodes

On AM64x devices, it is possible to route Main ESM0 error events to MCU
ESM. MCU ESM high error output can trigger the reset logic to reset the
device. So, for these devices we expect two ESM device nodes in the
device tree, one for Main ESM and the another MCU ESM in the device tree.
 When these ESM device nodes are properly configired it is possible to
route the Main RTI0 WWDT output to the MCU ESM high output through Main
ESM and trigger a device reset when
CTRLMMR_MCU_RST_CTRL:MCU_ESM_ERROR_RESET_EN_Z is set to '0'.

On K3 AM64x devices, the R5 SPL u-boot handles the ESM device node
configurations.

Signed-off-by: Hari Nagalla <hnagalla@ti.com>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>