staging: rtlwifi: remove unused RTLHALMAC_ST and RTLPHYDM_ST

Since nothing builds/depends on RTLHALMAC_ST and RTLPHYDM_ST, we could
remove them.
Furthermore, they are totally undocumented

Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>