staging: rtl8723bs: remove unnecessary logging in os_dep/wifi_regd.c

fix the following checkpatch.pl issues:

WARNING: Unnecessary ftrace-like logging - prefer using ftrace
153: FILE: drivers/staging/rtl8723bs/os_dep/wifi_regd.c:153:
+	DBG_8192C("%s\n", __func__);

Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
Link: https://lore.kernel.org/r/20210318152610.16758-16-fabioaiuto83@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>