cmis: Fix CLEI code parsing

In CMIS, unlike SFF-8636, there is no presence indication for the CLEI
code (Common Language Equipment Identification) field. The field is
always present, but might not be supported. In which case, "a value of
all ASCII 20h (spaces) shall be entered".

Therefore, remove the erroneous check which seems to be influenced from
SFF-8636 and only print the string if it is supported and has a non-zero
length.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>