staging: rtl8192e: Remove unused variable SifsTime

SifsTime is written and then never evaluated. Remove resulting dead code.

Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Link: https://lore.kernel.org/r/40234d0b1ab1eff23c71d96e8b0f1f0085e2bbac.1674071236.git.philipp.g.hortmann@gmail.com


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