staging: r8188eu: remove HW_VAR_SET_OPMODE from SetHwReg8188EU()

Remove the HW_VAR_SET_OPMODE case from SetHwReg8188EU() and move the
functions that are called by that case to rtw_mlme_ext.c. This is part
of the ongoing effort to get rid of SetHwReg8188EU().

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20220715062908.8547-2-straube.linux@gmail.com


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