mm/vmalloc: cleanup large_gfp in vm_area_alloc_pages()

mm/vmalloc: cleanup large_gfp in vm_area_alloc_pages()

Now that we have already checked for unsupported flags, we can use the
helper function to set the necessary gfp flags for the large order
allocation optimization.

Link: https://lkml.kernel.org/r/20251121094405.40628-4-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Acked-by: SeongJae Park <sj@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>