tpm2_createpolicy: make start_policy_session() more generic
tpm2_createpolicy: make start_policy_session() more generic

The start_policy_session() function gets a struct create_policy_ctx pointer
as a parameter, but the function logic is quite general so it can made more
generic by not tying it to a specifc tool context structructure.

Signed-off-by: Javier Martinez Canillas <8fdf2abf85d34ea8f3f979ef25dc1f25d94aca29@redhat.com>

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