Fixes the following Coccinelle/coccicheck warning reported by
minmax.cocci:

	WARNING opportunity for min()

Use const size_t instead of int for the result of min().

Compile-tested with CONFIG_KCSAN=y.
Reviewed-by: Marco Elver <elver@google.com>
Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>