[VTPM] VTPM manager -- Fix parameter check

[VTPM] VTPM manager -- Fix parameter check

If vtpm_managed is started with the same vtpm instance, the following
error occurs.

++++++++++++
 Loading NVM.
         Sending LoadNVM command
 INFO[VTSP]: Unbinding 256 bytes of data.
 ERROR in VTSP_Unbind at vtsp.c:719 code: TPM_BAD_PARAMETER.
 ERROR in envelope_decrypt at securestorage.c:156
 code:TPM_BAD_PARAMETER.
 ERROR[VTPM]: Failed to envelope decrypt data
 .ERROR in VTPM_Handle_Load_NVM at securestorage.c:284 code:
 TPM_BAD_PARAMETER.
 ERROR[VTPM]: Failed to load NVM
 .INFO[VTPM]: [VTPM Listener]: VTPM Listener waiting for messages.
         Reading LoadNVM header
++++++++++++

Signed-off-by: Kouichi YASAKI <yasaki.kouichi@jp.fujitsu.com>