scsi: nsp32: Remove unnecessary self assignment in nsp32_set_sync_entry

Clang warns:

drivers/scsi/nsp32.c:2444:14: warning: explicitly assigning value of
variable of type 'unsigned char' to itself [-Wself-assign]
        offset      = offset;
        ~~~~~~      ^

Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: GOTO Masanori <gotom@debian.or.jp>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>