qtbase: Disable freetype by default

* building qbasicfontdatabase fails without fontconfig enabled
  | /home/jenkins/webos-ports/workspace/webos-ports/tmp-eglibc/sysroots/a500/usr/include/ft2build.h:56:38:
    fatal error: freetype/config/ftheader.h: No such file or directory
  |  #include <freetype/config/ftheader.h>
  |                                       ^
  | compilation terminated.
  | make[2]: *** [.obj/release-shared/qbasicfontdatabase.o] Error 1
  | make[2]: *** Waiting for unfinished jobs....

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>