metag: hugetlbpage: Remove null pointer checks that could never happen

There are inconsistent NULL checks in
hugetlb_get_unmapped_area_existing(). The last conditional block in the
loop checks vma, but vma is dereferenced after that.

Due to the checks above however (bearing in mind after_huge is either 0
or 1) vma is guaranteed not to be NULL here, so remove that part of the
check.
Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
[james.hogan@imgtec.com: remove brackets and expand commit message]
Signed-off-by: James Hogan <james.hogan@imgtec.com>

arch/metag/mm/hugetlbpage.c

@@ -173,7 +173,7 @@ hugetlb_get_unmapped_area_existing(unsigned long len)
 				mm->context.part_huge = 0;
 			return addr;
 		}
-		if (vma && (vma->vm_flags & MAP_HUGETLB)) {
+		if (vma->vm_flags & MAP_HUGETLB) {
 			/* space after a huge vma in 2nd level page table? */
 			if (vma->vm_end & HUGEPT_MASK) {
 				after_huge = 1;