dts: arm64: intel: Enable Arm Timer for Intel Agilex SoC FPGA

This patch is to enable arm timer driver for Intel Agilex SoC FPGA.
The PPI's interrupt ID will be mapped into the interrupt ID
defined by SBSA in GIC-400 controller.

Signed-off-by: Teik Heng Chong <teik.heng.chong@intel.com>