Allow to select the manufacturer of TPM2

When using tpm2 simulator for boards like Betty that lack cr50 support,
it is necessary to change the manufacturer of the device. Otherwise,
several cr50 functions are enabled when returning the previous
manufacturer ID, breaking tests.

BUG=b:132144919
TEST=session.GuestAndActualSession, cryptohome.GuestSession hwsec.LoginGuest for board betty passes

Cq-Depend: chromium:2395142
Change-Id: If517ce97d03b376cde5054d34698946098e02aa3
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/tpm2/+/2395875
Reviewed-by: Andrey Pronin <apronin@chromium.org>
Reviewed-by: Leo Lai <cylai@google.com>
Tested-by: Alberto Herrera <ahrfgb@google.com>
Commit-Queue: Alberto Herrera <ahrfgb@google.com>
diff --git a/Makefile b/Makefile
index 626f46a..4f25d39 100644
--- a/Makefile
+++ b/Makefile
@@ -300,6 +300,10 @@
 Q :=
 endif
 
+
+ifneq ($(TPM2_SIMULATOR_MANUFACTURER),)
+CFLAGS += -DTPM2_SIMULATOR_MANUFACTURER
+endif
 ifeq ($(EMBEDDED_MODE),)
 SOURCES += $(HOST_SOURCES)
 CFLAGS += -Wall -Werror -fPIC
diff --git a/VendorString.h b/VendorString.h
index baf5164..1c62ccc 100644
--- a/VendorString.h
+++ b/VendorString.h
@@ -13,7 +13,12 @@
 //     definition should be replaced as appropriate when this code is used for
 //     actual implementations.
 //
+#ifdef        TPM2_SIMULATOR_MANUFACTURER
+#define        MANUFACTURER       "SIMU"
+#else
+//     Some CR50-specific functions expect this manufacturer.
 #define        MANUFACTURER       "CROS"
+#endif
 //
 //     The following #if macro may be deleted after a proper MANUFACTURER is provided.
 //