media: rc: gpio-ir-recv: Fix support for wake-up

[ Upstream commit 9c592f8ab114875fdb3b2040f01818e53de44991 ]

The driver was intended from the start to be a wake-up source for the
system, however due to the absence of a suitable call to
device_set_wakeup_capable(), the device_may_wakeup() call used to decide
whether to enable the GPIO interrupt as a wake-up source would never
happen. Lookup the DT standard "wakeup-source" property and call
device_init_wakeup() to ensure the device is flagged as being wakeup
capable.

Reported-by: Matthew Lear <matthew.lear@broadcom.com>
Fixes: fd0f6851 ("[media] rc: Add support for GPIO based IR Receiver driver")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>