Move pocl_cmd_max_grid_dim_width() outside HAVE_DLFCN_H
Move pocl_cmd_max_grid_dim_width() outside HAVE_DLFCN_H

some build configs that don't use dlopen() require it

franz/pocl,pocl/pocl,pocl/pocl,franz/pocl,pocl/pocl,pocl/pocl,franz/pocl,franz/pocl,franz/pocl,pocl/pocl