staging: rtl8723bs: remove set but not used variable 'bWifiBusy'

staging: rtl8723bs: remove set but not used variable 'bWifiBusy'

Fixes gcc '-Wunused-but-set-variable' warning:

 In function halbtc8723b1ant_TdmaDurationAdjustForAcl:
drivers/staging/rtl8723bs/hal/HalBtc8723b1Ant.c:1761:7: warning:
 variable bWifiBusy set but not used [-Wunused-but-set-variable]

It is never used so can be removed.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190726140321.19200-1-yuehaibing@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>