scsi: libfc: remove redundant initialization of 'disc'

Pointer disc is being intializated a value that is never read and then
re-assigned the same value later on, hence the initialization is
redundant and can be removed.

Cleans up clang warning:
drivers/scsi/libfc/fc_disc.c:734:18: warning: Value stored to 'disc'
during its initialization is never read

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Johannes Thumshirn <jth@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>