mm: vmalloc: remove redundant assignment in unmap_kernel_range_noflush()

'addr' is set to 'start' and then a few lines afterwards 'start' is set to
'addr'.  Remove the second asignment.

Fixes: 2ba3e69 ("mm/vmalloc: track which page-table levels were modified")
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Joerg Roedel <jroedel@suse.de>
Link: http://lkml.kernel.org/r/20200707163226.374685-1-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmalloc.c

@@ -175,7 +175,6 @@ void unmap_kernel_range_noflush(unsigned long start, unsigned long size)
 	pgtbl_mod_mask mask = 0;
 
 	BUG_ON(addr >= end);
-	start = addr;
 	pgd = pgd_offset_k(addr);
 	do {
 		next = pgd_addr_end(addr, end);