tpm: Don't implement scatter-gather in transmit()

tpm: Don't implement scatter-gather in transmit()

There are no longer any callers to transmit() that use multiple
buffers.  Simplify transmit() so that it takes a single request
buffer.

The pass_through_to_tpm() wrapper around transmit() is no longer
needed.  Remove the function and have all callers use transmit()
directly.

Now that tpm_extend() function calls transmit directly, it can use
TPM_DURATION_TYPE_SHORT duration.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>