arm64: remove return value form psci_init()

arm64: remove return value form psci_init()

psci_init() is written to return err code if something goes wrong. However,
the single user, setup_arch(), doesn't care about it. Moreover, every error
path is supplied with a clear message which is enough for pleasant debugging.

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
(cherry picked from commit 64b4f60f497058f1c6ba118a0260249ee5c091a6)
Signed-off-by: Mark Brown <broonie@linaro.org>