staging: r8188eu: remove some dead code

In this driver SupportICType is ODM_RTL8188E and SupportInterface is
ODM_ITRF_USB. Remove an if statement that is never true and remove
function odm_DIGbyRSSI_LPS() which is used only in this dead if block.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20211008172621.8721-1-straube.linux@gmail.com


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