scsi: qedf: Avoid reading past end of buffer

Using memcpy() from a string that is shorter than the length copied
means the destination buffer is being filled with arbitrary data from
the kernel rodata segment. Instead, use strncpy() which will fill the
trailing bytes with zeros.

This was found with the future CONFIG_FORTIFY_SOURCE feature.

Cc: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Chad Dupuis <chad.dupuis@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>