proc: test /proc/self/syscall

Read from /proc/self/syscall should yield read system call and correct
args in the output as current is reading /proc/self/syscall.

Link: http://lkml.kernel.org/r/20180226212145.GB742@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/tools/testing/selftests/proc/Makefile b/tools/testing/selftests/proc/Makefile
index 592603a..ad20520 100644
--- a/tools/testing/selftests/proc/Makefile
+++ b/tools/testing/selftests/proc/Makefile
@@ -1,6 +1,7 @@
 CFLAGS += -Wall -O2
 
 TEST_GEN_PROGS :=
+TEST_GEN_PROGS += proc-self-syscall
 TEST_GEN_PROGS += proc-self-wchan
 
 include ../lib.mk