rtlwifi: Remove temporary definition of RT_TRACE

A definition of this macro was kept until all drivers had been converted.
It can now be deleted.

This change also renames _rtl_dbg_trace() to _rtl_dbg_out().

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200831185046.30307-1-Larry.Finger@lwfinger.net