ARM: qcom: Add qcom,msm8916-smp enable-method identical to MSM8226

Unfortunately, some MSM8916 devices have signed firmware without
ARM64 and PSCI support and can therefore only boot ARM32 Linux.
The ARM Cortex-A53 cores should be actually booted exactly like
the Cortex-A7 cores on MSM8226, so just add an alias for the
existing code.

Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211004204955.21077-9-stephan@gerhold.net