Change the type of partitionSizeTmp from u32 to __be32 to suppress the
sparse warning:

warning: cast to restricted __be32

Link: https://lore.kernel.org/r/20220220031810.738362-4-damien.lemoal@opensource.wdc.comReviewed-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>