spmi: spmi-pmic-arb: enable the SPMI interrupt as a wakeup source

Currently the SPMI interrupt will not wake the device. Enable this
interrupt as a wakeup source.

Signed-off-by: Nicholas Troast <ntroast@codeaurora.org>
Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>