staging: r8188eu: BTRxRSSIPercentage is set but never used

BTRxRSSIPercentage is set but never used, remove it from structure
phy_info.

Acked-by: Martin Kaiser <martin@kaiser.cx>
Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20211019135137.9893-3-straube.linux@gmail.com


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