staging: rtl8192e: Remove unused variables bShortPreamble and fragoffset

Remove unused variables bShortPreamble and fragoffset as they are set and
never evaluated.

Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Link: https://lore.kernel.org/r/17c516c195acc458366ab182e0fd1200b7e2b1da.1708461563.git.philipp.g.hortmann@gmail.com


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