remoteproc: qcom_wcnss: Handle platforms with only single power domain

Both MSM8974 and MSM8226 have only CX as power domain with MX & PX being
handled as regulators. Handle this case by reodering pd_names to have CX
first, and handling that the driver core will already attach a single
power domain internally.

Signed-off-by: Matti Lehtimäki <matti.lehtimaki@gmail.com>
[luca: minor changes]
Signed-off-by: Luca Weiss <luca@lucaweiss.eu>
Link: https://lore.kernel.org/r/20250206-wcnss-singlepd-v2-2-9a53ee953dee@lucaweiss.eu


[bjorn: Added missing braces to else after multi-statement if]
Signed-off-by: Bjorn Andersson <andersson@kernel.org>