arm64: psci: Update the print in cpu_psci_cpu_init()

There is no PSCO word, so update the print message in
cpu_psci_init() function with appropriate term -
Power State Coordination Interface (PSCI).

Change-Id: I0f6035647b99bf27ccf6ef8f3714cf673f2ef756
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>