rtlwifi: rtl8192cu: remove _InitBeaconParameters().

_InitBeaconParameters() and rtl92cu_init_beacon_parameters() is
same routine. I remove both functions. then i add
_rtl92cu_init_beacon_parameters() in the hw.c.
_rtl92cu_init_beacon_parameters() is same routine with
_InitBeaconParameters().

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