ARMv8: LS1043A: Enable LS1043A default PSCI support

A most basic PSCI implementation with only one psci_version is added for
LS1043A, this can verify the generic PSCI framework, and more platform specific
implementation will be added later.

Signed-off-by: Hongbo Zhang <hongbo.zhang@nxp.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: York Sun <york.sun@nxp.com>