scsi: qedi: Fix truncation of CHAP name and secret

The data in NVRAM is not guaranteed to be NUL terminated.  Since
snprintf expects byte-stream to accommodate null byte, the CHAP secret
is truncated.  Use sprintf instead of snprintf to fix the truncation of
CHAP name and secret.

Signed-off-by: Andrew Vasquez <andrew.vasquez@cavium.com>
Signed-off-by: Nilesh Javali <nilesh.javali@cavium.com>
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Acked-by: Chris Leech <cleech@redhat.com>
Acked-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>