OvmfPkg/Tcg2ConfigPei: generalize TPM2-only file-top comments

OvmfPkg/Tcg2ConfigPei: generalize TPM2-only file-top comments

The leading comments in "Tcg2ConfigPei.inf" and "Tcg2ConfigPeim.c" say,
"In OvmfPkg, the module only performs TPM2 hardware detection".

The statement hasn't been correct since commit 89236992913f ("OvmfPkg:
detect TPM 1.2 in Tcg2ConfigPei", 2020-03-04). Replace "TPM2" with "TPM"
(without stating a version) in those file-top comments.

Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Cc: Stefan Berger <stefanb@linux.ibm.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2752
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20200603170413.23936-2-lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>