staging: lustre: Use is_vmalloc_addr

Instead of manually checking the bounds of VMALLOC_START and
VMALLOC_END, just use is_vmalloc_addr. That's what the function
was designed for.

Signed-off-by: Laura Abbott <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c

···
 {
 	struct page *page;
 
-	if (vaddr >= VMALLOC_START &&
-	    vaddr < VMALLOC_END) {
+	if (is_vmalloc_addr(vaddr)) {
 		page = vmalloc_to_page ((void *)vaddr);
 		LASSERT (page != NULL);
 		return page;