rtl8723au: Fix Smatch warnings in core/rtw_xmit.c

Smatch reports the following:

  CHECK   /home/finger/rtl8723au/core/rtw_xmit.c
/home/finger/rtl8723au/core/rtw_xmit.c:2068 rtw_alloc_hwxmits() error: buffer overflow 'hwxmits' 4 <= 4

This results from an off-by-one error.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
rtl8723au: Fix Smatch warnings in hal/rtl8723a_bt-coexist.c

Smatch lists the following:

 CHECK   /home/finger/rtl8723au/hal/rtl8723a_bt-coexist.c
/home/finger/rtl8723au/hal/rtl8723a_bt-coexist.c:1875 bthci_BuildLogicalLink() warn: buffer overflow 'pHciCmd->Data' 2 <= 17
/home/finger/rtl8723au/hal/rtl8723a_bt-coexist.c:2626 bthci_CmdEnhancedFlush() error: buffer overflow 'pHciCmd->Data' 2 <= 2
/home/finger/rtl8723au/hal/rtl8723a_bt-coexist.c:2879 bthci_CmdWriteLocationData() error: buffer overflow 'pHciCmd->Data' 2 <= 3
/home/finger/rtl8723au/hal/rtl8723a_bt-coexist.c:2880 bthci_CmdWriteLocationData() error: buffer overflow 'pHciCmd->Data' 2 <= 4
/home/finger/rtl8723au/hal/rtl8723a_bt-coexist.c:3897 bthci_CmdFlowSpecModify() warn: buffer overflow 'pHciCmd->Data' 2 <= 2
/home/finger/rtl8723au/hal/rtl8723a_bt-coexist.c:3899 bthci_CmdFlowSpecModify() warn: buffer overflow 'pHciCmd->Data' 2 <= 18
/home/finger/rtl8723au/hal/rtl8723a_bt-coexist.c:4151 bthci_CmdSetRSSIValue() error: buffer overflow 'pHciCmd->Data' 2 <= 2
/home/finger/rtl8723au/hal/rtl8723a_bt-coexist.c:4151 bthci_CmdSetRSSIValue() error: buffer overflow 'pHciCmd->Data' 2 <= 2
/home/finger/rtl8723au/hal/rtl8723a_bt-coexist.c:5758 bthci_UseFakeData() warn: buffer overflow 'pHciCmd->Data' 2 <= 17
/home/finger/rtl8723au/hal/rtl8723a_bt-coexist.c:5764 bthci_UseFakeData() warn: buffer overflow 'pHciCmd->Data' 2 <= 2
/home/finger/rtl8723au/hal/rtl8723a_bt-coexist.c:5765 bthci_UseFakeData() warn: buffer overflow 'pHciCmd->Data' 2 <= 18

An array in one of the structs was of size 2, and should have been at least 19. It is now 20.

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