tpm2_loadexternal: remove unique file name check
tpm2_loadexternal: remove unique file name check

Remove the code that verifies that the -c option is unique and
doesn't exist. This is a holdover that needed to be removed as
we just use whatever is specified in -c as is.

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

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