Add autoconf test for CAN.

Signed-off-by: Zeng Linggang <zenglg.jy@cn.fujitsu.com>
diff --git a/configure.ac b/configure.ac
index 0e1c3b8..8f03af1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -187,5 +187,6 @@
 LTP_CHECK_TEE
 LTP_CHECK_SPLICE
 LTP_CHECK_VMSPLICE
+LTP_CHECK_CAN_SUPPORT
 
 AC_OUTPUT