regression: add case 8103

Adds regression case 8103 which uses the TAF TA_CRYPT_CMD_MBED_SIGN_CERT
to sign a certificate using a CSR. Output is the X.509 certificate and a
certificate chain used to verify the certificate.

Tested-by: Jerome Forissier <jerome.forissier@linaro.org> (HiKey960)
Tested-by: Jens Wiklander <jens.wiklander@linaro.org> (QEMU)
Acked-by: Jerome Forissier <jerome.forissier@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/host/xtest/Makefile b/host/xtest/Makefile
index 6b666a7..b4d18f3 100644
--- a/host/xtest/Makefile
+++ b/host/xtest/Makefile
@@ -217,6 +217,7 @@
 $(eval $(call embed-file,regression_8100_ca_crt,../../cert/ca.crt))
 $(eval $(call embed-file,regression_8100_mid_crt,../../cert/mid.crt))
 $(eval $(call embed-file,regression_8100_my_crt,../../cert/my.crt))
+$(eval $(call embed-file,regression_8100_my_csr,../../cert/my.csr))
 
 .PHONY: clean
 clean: