arm64/hyperv: Use CPUHP_AP_HYPERV_ONLINE state to fix CPU online sequencing

arm64/hyperv: Use CPUHP_AP_HYPERV_ONLINE state to fix CPU online sequencing

State CPUHP_AP_HYPERV_ONLINE has been introduced to correctly sequence the
initialization of hyperv_pcpu_input_arg. Use this new state for Hyper-V
initialization so that hyperv_pcpu_input_arg is allocated early enough.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Link: https://lore.kernel.org/r/1684862062-51576-2-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>