staging: mt7621-mmc: delele extra blank lines

Delete extra blank lines to mute checkpatch.pl check:
CHECK: Please don't use multiple blank lines

Signed-off-by: Wentao Cai <etsai042@gmail.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>