arm64: psci: kill psci_power_state

A PSCI 1.0 implementation may choose to use the new extended StateID
format, the presence of which may be queried via the PSCI_FEATURES call.
The layout of this new StateID format is incompatible with the existing
format, and so to handle both we must abstract attempts to parse the
fields.

In preparation for PSCI 1.0 support, this patch introduces
psci_power_state_loses_context and psci_power_state_is_valid functions
to query information from a PSCI power state, which is no longer
decomposed (and hence the pack/unpack functions are removed). As it is
no longer decomposed, it is now passed round as an opaque u32 token.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>