staging: r8188eu: replace leading spaces by tabs

Spaces are prohibited as per the Linux coding style guidelines. Replace
those by tabs wherever possible to improve code alignment. Error
reported by checkpatch script.

Signed-off-by: Deepak R Varma <drv@mailo.com>
Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Link: https://lore.kernel.org/r/c32b702c61ea3367d60f0a4c2443093d6ce45a69.1666299151.git.drv@mailo.com


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