rtlwifi: Start changing RT_TRACE into rtl_dbg

The macro name RT_TRACE makes it seem that it is used for tracing, when
is actually used for debugging. Change the name to RT_DEBUG.

This step creates the new macro while keeping the old RT_TRACE to allow
building. It will be removed at the end of the patch series.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200723204244.24457-2-Larry.Finger@lwfinger.net