scsi: isci: remove redundant initialization to 'bit'

Variable bit is initialized with a value that is never read and is being
updated immediately after the initialization, hence the initialization
is redundant and can be removed.

Cleans up clang warning:
drivers/scsi/isci/host.c:2769:8: warning: Value stored to 'bit' during
its initialization is never read

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>