rtl8723au: Fix smatch warnings in CHECK /home/finger/rtl8723au/hal/odm_HWConfig.c

rtl8723au: Fix smatch warnings in   CHECK   /home/finger/rtl8723au/hal/odm_HWConfig.c

Smatch lists the following:
/home/finger/rtl8723au/hal/odm_HWConfig.c:400 odm_RxPhyStatus92CSeries_Parsing() warn: always true condition '(pPktinfo->Rate >= 0) => (0-255 >= 0)'
/home/finger/rtl8723au/hal/odm_HWConfig.c:783 odm_Process_RSSIForDM() warn: always true condition '(pPktinfo->Rate >= 0) => (0-255 >= 0)'

Variable Rate is unsigned and always >= 0.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>