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/shared/efi-loader.c

@@ -7,7 +7,7 @@
 #include "path-util.h"
 #include "stat-util.h"
 #include "strv.h"
-#include "tpm-pcr.h"
+#include "tpm2-pcr.h"
 #include "utf8.h"
 
 #if ENABLE_EFI