hw/sd/sdcard: Update coding style to make checkpatch.pl happy

hw/sd/sdcard: Update coding style to make checkpatch.pl happy

To make the next commit easier to review, clean this code first.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20200630133912.9428-3-f4bug@amsat.org>
(cherry picked from commit 794d68de2f021a6d3874df41d6bbe8590ec05207)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>