ixp4xx-beeper: add MODULE_ALIAS

The following patch allows ixp4xx-beeper to be loaded by udev
automatically when compiled as a module with kernel versions 2.4.24 and
greater.

This patch is required because 43cc71ee


("platform: prefix MODALIAS with "platform:"") changed the modalias
string to have the extra prefix.

LKG7102D7:~# udevinfo -a -p /sys/devices/platform/ixp4xx-beeper.4

 looking at device '/devices/platform/ixp4xx-beeper.4':
   KERNEL=="ixp4xx-beeper.4"
   SUBSYSTEM=="platform"
   DRIVER==""
   ATTR{modalias}=="platform:ixp4xx-beeper"

udev therefore tries to modprobe platform:ixp4xx-beeper instead of
ixp4xx-beeper.

LKG7102D7:~# udevtest /sys/devices/platform/ixp4xx-beeper.4
...
import_uevent_var: import into environment: 'PHYSDEVBUS=platform'
import_uevent_var: import into environment: 'MODALIAS=platform:ixp4xx-beeper'
main: looking at device '/devices/platform/ixp4xx-beeper.4' from
subsystem 'platform'
wait_for_sysfs: file '/sys/devices/platform/ixp4xx-beeper.4/bus'
appeared after 0 loops
main: run: 'socket:/org/kernel/udev/monitor'
main: run: '/sbin/modprobe --use-blacklist platform:ixp4xx-beeper'

With this patch, depmod adds an alias line (see below) to
modules.alias which allows modprobe to load the right module.

alias platform:ixp4xx-beeper ixp4xx-beeper

Signed-off-by: Gordon Farquharson <gordonfarquharson@gmail.com>
Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>