staging: rtl8188eu: Fix an indent coding style issue

Only a single tab space is required after the if statement.
Fix this issue by running scripts/checkpatch.pl on the file.
Signed-off-by: Mrinal Pandey <mrinalmni@gmail.com>
Link: https://lore.kernel.org/r/20200722151900.5dcebtavkdi5cc77@mrinalpandeySigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>