staging: rtl8192e: Remove variable modulation as it is constant

ieee->modulation is initialized to 3 and then unchanged. All evaluations
will result accordingly. Remove resulting dead code.

Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Link: https://lore.kernel.org/r/ebd543d097a65f105078c71faceaed2a4d5e7b55.1687583718.git.philipp.g.hortmann@gmail.com


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