test: Remove ASN1 library test

With MBEDTLS_LIB_X509 enabled, we don't build the original ASN1 lib,
So remove it from test.

Signed-off-by: Raymond Mao <raymond.mao@linaro.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/test/Kconfig b/test/Kconfig
index e2ec099..558a9cd 100644
--- a/test/Kconfig
+++ b/test/Kconfig
@@ -32,7 +32,7 @@
 
 config UT_LIB_ASN1
 	bool "Unit test for asn1 compiler and decoder function"
-	depends on SANDBOX
+	depends on SANDBOX && !MBEDTLS_LIB_X509
 	default y
 	imply ASYMMETRIC_KEY_TYPE
 	imply ASYMMETRIC_PUBLIC_KEY_SUBTYPE