Updated host/tools_support.c for new get_user_pages() function.

Updated host/tools_support.c for new get_user_pages() function.

At some point the function prototype changed from this:

    long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                unsigned long start, unsigned long nr_pages,
                int write, int force, struct page **pages,
                struct vm_area_struct **vmas);

into this:

    long get_user_pages(unsigned long start, unsigned long nr_pages,
                    unsigned int gup_flags, struct page **pages,
                    struct vm_area_struct **vmas);

With the individual 'write' and 'force' flags transforming into gup_flags per
this patch:

    https://patchwork.kernel.org/project/linux-arm-kernel/patch/20161013002020.3062-7-lstoakes@gmail.com/