mfd: wcd9xxx: send down notification to devices before cleaning-up IRQs

IRQ clean up should be done only after codec devices have been
notified with device down. Without this, there are chances of
race-condition where some of the resources like locks used for
safe handling of the IRQs would be used after those are freed.

CRs-Fixed: 1102353
Change-Id: I276571a7e50fcf227febd86494589b14988e3d41
Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org>
Signed-off-by: Bhalchandra Gajare <gajare@codeaurora.org>