staging: rtl8723bs: Replace function beacon_timing_control()

Remove function beacon_timing_control as it does nothing except call
rtw_hal_bcn_related_reg_setting.
Rename rtw_hal_bcn_related_reg_setting to beacon_timing_control to
maintain compatibility with call site.
Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Link: https://lore.kernel.org/r/20190725052645.2372-6-nishkadg.linux@gmail.com


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