selftests: android: ion: Fix ionmap_test compile error

ionmap_test compile rule is missing ipcsocket.c dependency. Add it to
fix the following compile errors:

..android/ion/ionutils.c:221: undefined reference to `sendtosocket'
..android/ion/ionutils.c:243: undefined reference to `receivefromsocket'

Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>