tpm: fix GetCapability calls to use the correct pointer

The additions of ScopedTssMemory introduced a little weirdness
and the *cap meme was leftover work from an earlier version. However,
it is wrong.  This changes fixes that wrong-ness.

TEST=unittests pass; builds works
BUG=chromium-os:13129

Change-Id: Ie45e97af8a14a30dc8a8121950b88b105399dd48

R=gauravsh@chromium.org

Review URL: http://codereview.chromium.org/6731069
diff --git a/tpm.cc b/tpm.cc
index 3a1c130..ee04c92 100644
--- a/tpm.cc
+++ b/tpm.cc
@@ -630,7 +630,7 @@
     return count;
   }
   if (cap_length == sizeof(unsigned int)) {
-    count = *(reinterpret_cast<unsigned int*>(*cap));
+    count = *(reinterpret_cast<unsigned int*>(*cap.ptr()));
   }
   return count;
 }
@@ -1085,7 +1085,7 @@
                                        &cap_length, cap.ptr())) == 0) {
     if (cap_length >= (sizeof(TSS_BOOL))) {
       *enabled = true;
-      *owned = ((*(reinterpret_cast<TSS_BOOL*>(*cap))) != 0);
+      *owned = ((*(reinterpret_cast<TSS_BOOL*>(*cap.ptr()))) != 0);
     }
   } else if(ERROR_CODE(result) == TPM_E_DISABLED) {
     *enabled = false;