staging: r8188eu: PHY_SetRFPathSwitch_8188E is not used

Remove the PHY_SetRFPathSwitch_8188E function which is not used.

It was the only caller of phy_setrfpathswitch_8188e, that function
can be removed as well.

Acked-by: Michael Straube <straube.linux@gmail.com>
Acked-by: Phillip Potter <phil@philpotter.co.uk>
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20211016113008.27549-6-martin@kaiser.cx


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