mini-os/tpmback: set up callbacks before enumeration

The open/close callbacks in tpmback cannot be properly initalized in
order to catch the initial enumeration events because init_tpmback
clears the callbacks and then asynchronously starts the enumeration of
existing tpmback devices. Fix this by passing the callbacks to
init_tpmback so they can be installed before enumeration.

This also removes the unused callbacks for suspend and resume.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>

stubdom/vtpm/vtpm.c

@@ -367,7 +367,7 @@ int main(int argc, char **argv)
    }
 
    /* Initialize devices */
-   init_tpmback();
+   init_tpmback(NULL, NULL);
    if((tpmfront_dev = init_tpmfront(NULL)) == NULL) {
       error("Unable to initialize tpmfront device");
       goto abort_posttpmfront;

stubdom/vtpmmgr/init.c

@@ -462,7 +462,7 @@ TPM_RESULT vtpmmgr_init(int argc, char** argv) {
    }
 
    //Setup tpmback device
-   init_tpmback();
+   init_tpmback(NULL, NULL);
 
    //Setup tpm access
    switch(opts.tpmdriver) {