floppy: cleanup: remove redundant assignment to nr_sectors

floppy: cleanup: remove redundant assignment to nr_sectors

Variable nr_sectors is set to zero but this value is never
read as it is overwritten later on, hence it is a redundant
assignment and can be removed.

Clean up the following clang-analyzer warning:

drivers/block/floppy.c:2333:2: warning: Value stored to 'nr_sectors' is
never read [clang-analyzer-deadcode.DeadStores].

Link: https://lore.kernel.org/r/1619774805-121562-1-git-send-email-jiapeng.chong@linux.alibaba.com
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Denis Efremov <efremov@linux.com>