tpm2_nvdefine: issue a warning on size 0 defines
tpm2_nvdefine: issue a warning on size 0 defines

Defining an nv index with a size of 0 is valid, however,
the index is essentially unusable for storing data.

Issue a warning on size 0 index sizes.

Signed-off-by: William Roberts <60148e894dabf0b83bde1d460768794cd453c455@intel.com>

01org/tpm2.0-tools,martinezjavier/tpm2-tools,martinezjavier/tpm2-tools,martinezjavier/tpm2-tools,01org/tpm2.0-tools,martinezjavier/tpm2-tools,01org/tpm2.0-tools