Commit ef8b4520 added one NULL check for
"p" in krealloc(), but that doesn't seem to be enough since there
doesn't seem to be any guarantee that memcpy(ret, NULL, 0) works
(spotted by the Coverity checker).

For making it clearer what happens this patch also removes the pointless
min().
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Acked-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>