sphinx: remove unused imports from conf.py
sphinx: remove unused imports from conf.py

The file is autogenerated from a template and includes these imports for
an option that is commented out. Remove the imports to make lgtm.com
happy.

Signed-off-by: Jonas Witschel <87a164e5d00d5dcdd001e37b34ea8bcd3fc3a172@gmx.de>

01org/TPM2.0-TSS,01org/tpm2-tss,01org/tpm2-tss,01org/tpm2-tss,01org/TPM2.0-TSS,01org/TPM2.0-TSS,tpm2-software/tpm2-tss,tpm2-software/tpm2-tss,01org/TPM2.0-TSS,tpm2-software/tpm2-tss