staging: r8188eu: pNumTxBytesUnicast is set but never used

pNumTxBytesUnicast in odm_dm_struct is set but never used.
Remove it.

Acked-by: Martin Kaiser <martin@kaiser.cx>
Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20211202192309.9362-5-straube.linux@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>