staging: rtl8723au: hal: odm.c: Remove some unused functions

Removes some functions that are not used anywhere:
odm_1R_CCA23a() odm_TXPowerTrackingCheckAP() odm_TXPowerTrackingCheckMP()
odm_RSSIMonitorCheck23aAP() odm_RSSIMonitorCheck23aMP() odm_RSSIMonitorInit()
odm_RefreshRateAdaptiveMask23aAPADSL23a() odm_RefreshRateAdaptiveMask23aMP23a()

This was partially found by using a static code analysis program called cppcheck.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>