staging: rtl8723bs: HalBtc8723b1Ant.c: fix build warnings about unused variables

staging: rtl8723bs: HalBtc8723b1Ant.c: fix build warnings about unused variables

0-day keeps spitting out annoying messages:

drivers/staging/rtl8723bs/hal/HalBtc8723b1Ant.c:2117:6: warning: variable 'u4Tmp' set but not used [-Wunused-but-set-variable]
drivers/staging/rtl8723bs/hal/HalBtc8723b1Ant.c:2118:17: warning: variable 'u1Tmpb' set but not used [-Wunused-but-set-variable]
drivers/staging/rtl8723bs/hal/HalBtc8723b1Ant.c:2118:5: warning: variable 'u1Tmpa' set but not used [-Wunused-but-set-variable]

So fix this up by just removing the storage of the values read.  Leave
the read from the hardware as odds are it is required in order to keep
it working properly as I do not have the hardware to test with.

Link: https://lore.kernel.org/r/20210520064133.1953156-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>