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>

tools/testing/selftests/android/ion/Makefile

@@ -17,4 +17,4 @@ include ../../lib.mk
 
 $(OUTPUT)/ionapp_export: ionapp_export.c ipcsocket.c ionutils.c
 $(OUTPUT)/ionapp_import: ionapp_import.c ipcsocket.c ionutils.c
-$(OUTPUT)/ionmap_test: ionmap_test.c ionutils.c
+$(OUTPUT)/ionmap_test: ionmap_test.c ionutils.c ipcsocket.c