fundamental: rename tpm-pcr.h → tpm2-pcr.h

I always found it confusing that most of our TPM related definitions are
in tpm2-util.h, but the PCR names in tpm-pcr.h, without the "2". Let's
fix that and make this systematic, in particular as the definitions in
the file all start with TPM2_ already.

No code flow changes, just some renaming.

src/cryptenroll/cryptenroll.c

@@ -27,7 +27,7 @@
 #include "string-table.h"
 #include "strv.h"
 #include "terminal-util.h"
-#include "tpm-pcr.h"
+#include "tpm2-pcr.h"
 
 static EnrollType arg_enroll_type = _ENROLL_TYPE_INVALID;
 static char *arg_unlock_keyfile = NULL;