staging: r8188eu: replace tabs with space in odm_query_rxpwrpercentage()

In statements spaces should be used not tabs. Replace tabs withs spaces
in two return statements in odm_query_rxpwrpercentage().

Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20220911161949.11293-7-straube.linux@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>