rtlwifi: rtl8192cu: remove duplicated routine in hw.c and mac.c

rtl92c_set_xxx_filter is same routine with rtl92cu_set_hw_reg.
so i remove those functions that are rtl92c_set_xxx_filter.
(rtl92c_get_xxx_filter is also same reason.)
also i add code updating struct rtl_mac member variable in the
rtl92cu_set_hw_reg.
after that, no more _update_mac_setting is not useful. thus i remove that.

Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>