staging: r8188eu: remove rf_type from storePwrIndexDiffRateOffset()

pHalData->rf_type is always RF_1T1R. Remove unnecessary checks and
related dead code from storePwrIndexDiffRateOffset().

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20211128170924.5874-4-straube.linux@gmail.com


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