arm: mach-k3: am62px: introduce clock and device files for wkup spl

Include the clock and lpsc tree files needed for the wkup spl to
initialize the proper PLLs and power domains to boot the SoC.

Reviewed-by: Neha Malcom Francis <n-francis@ti.com>
Signed-off-by: Bryan Brattlof <bb@ti.com>