Make TPM errors less fatal

Handle TPM errors, and stop trying to use the TPM once we hit one.

grub-core/loader/multiboot.c

@@ -386,6 +386,7 @@ grub_cmd_module (grub_command_t cmd __attribute__ ((unused)),
 
   grub_file_close (file);
   grub_tpm_measure (module, size, GRUB_BINARY_PCR, "grub_multiboot", argv[0]);
+  grub_print_error();
   return GRUB_ERR_NONE;
 }