soc: swr: Add wakeup source for swr device

Voice call over headset does not disconnect on button press
while device is in suspend state. This is because inband interrupt
is not made wakeup capable. Make inband interrupt for swr tx as
wakeup capable. Also add wakeup source for swr device.

Change-Id: I5f2751672675bc8d62c4d2bfbbd651e640723d52
Signed-off-by: Vatsal Bucha <vbucha@codeaurora.org>