configs: enable SEMIHOSTING on qemu_arm64_defconfig

We need a platform on which we can test our semihosting code.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Sean Anderson <sean.anderson@seco.com>
diff --git a/configs/qemu_arm64_defconfig b/configs/qemu_arm64_defconfig
index 94bd966..2080f5e 100644
--- a/configs/qemu_arm64_defconfig
+++ b/configs/qemu_arm64_defconfig
@@ -71,4 +71,5 @@
 CONFIG_USB=y
 CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_EHCI_PCI=y
+CONFIG_SEMIHOSTING=y
 CONFIG_TPM=y