[PATCH] kernel/param.c: don't use .max when .num is NULL in param_array_set()

there seems to be a bug, at least for me, in kernel/param.c for arrays with
.num == NULL.  If .num == NULL, the function param_array_set() uses &.max
for the call to param_array(), wich alters the .max value to the number of
arguments.  The result is, you can't set more array arguments as the last
time you set the parameter.

example:

# a module 'example' with
# static int array[10] = { 0, };
# module_param_array(array, int, NULL, 0644);

$ insmod example.ko array=1,2,3
$ cat /sys/module/example/parameters/array
1,2,3
$ echo "4,3,2,1" > /sys/module/example/parameters/array
$ dmesg | tail -n 1
kernel: array: can take only 3 arguments

Signed-off-by: Bert Wesarg <wesarg@informatik.uni-halle.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>