man/tpm2_changeauth: replace -a with -C
man/tpm2_changeauth: replace -a with -C

Signed-off-by: Remus Wu <cdbdd134f0f578e6da930807006d9b37a2716c36@gmail.com>

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