configs: enable CMD_TPM on QEMU ARM

With TPM emulation enabled in u-boot-test-hooks we should also provide the
tpm2 command used for the test/py/tests/test_tpm2.py test.

One of the Python TPMv2 tests expects sandbox specific values. So disable
it on other platforms.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/configs/qemu_arm_defconfig b/configs/qemu_arm_defconfig
index ab55748..b459305 100644
--- a/configs/qemu_arm_defconfig
+++ b/configs/qemu_arm_defconfig
@@ -25,6 +25,7 @@
 CONFIG_CMD_MTD=y
 CONFIG_CMD_PCI=y
 CONFIG_CMD_USB=y
+CONFIG_CMD_TPM=y
 CONFIG_CMD_MTDPARTS=y
 CONFIG_OF_BOARD=y
 CONFIG_ENV_IS_IN_FLASH=y