tools: fix kcmp_test compile warnings

kcmp_test.c: In function ‘main’:
kcmp_test.c:85:5: warning: format ‘%li’ expects argument of type ‘long int’, but argument 2 has type ‘int’ [-Wformat=]
     ret, strerror(errno));
     ^

Signed-off-by: Shuah Khan <shuah.kh@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>