i2c: smbus: Don't filter out duplicate alerts

[ Upstream commit dca0dd28fa5e0a1ec41a623dbaf667601fc62331 ]

Getting the same alert twice in a row is legal and normal,
especially on a fast device (like running in qemu).  Kind of
like interrupts.  So don't report duplicate alerts, and deliver
them normally.

[JD: Fixed subject]

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Stable-dep-of: f6c29f710c1f ("i2c: smbus: Send alert notifications to all devices if source not found")
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 6adca954fc039151ef4f9c1ea1f201e12a24593d)
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>