mariadb: update for packgeconfig valgrind

When 'valgrind' is not in PACKAGECONFIG, 'WITHOUT_VALGRIND' is passed to
cmake but it is not a valid cmake macro. Warning messages show in
log.do_configure:

CMake Warning:
  Manually-specified variables were not used by the project:
    WITHOUT_VALGRIND

Use -DWITH_VALGRIND=FALSE instead.

Signed-off-by: Kai Kang <kai.kang@windriver.com>
Signed-off-by: Randy MacLeod <Randy.MacLeod@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>