mm/vmalloc: update the header about KVA rework

Reflect information about the author, date and year when the KVA rework
was done.
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200622195821.4796-1-urezki@gmail.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmalloc.c

@@ -7,6 +7,7 @@
  *  SMP-safe vmalloc/vfree/ioremap, Tigran Aivazian <tigran@veritas.com>, May 2000
  *  Major rework to support vmap/vunmap, Christoph Hellwig, SGI, August 2002
  *  Numa awareness, Christoph Lameter, SGI, June 2005
+ *  Improving global KVA allocator, Uladzislau Rezki, Sony, May 2019
  */
 
 #include <linux/vmalloc.h>