github: don't use matrix on fixed vars
github: don't use matrix on fixed vars

If the list has only one element, no need to complicate it with using a
matrix and substitution.

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

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