Any update to the SRNG TP/HP when the device is in low power
state would result in system errors. While in D3 WoW mode,
disable EXT grp irqs and drain TXRX before sending enter
power save mode to the FW. This will ensure that no interrupts
are received while in WoW mode and as a result there wont be any
HP/TP updates.
Change-Id: Ic1fb7fdd45096b458abf5d243fa652c3da878dc0
CRs-Fixed: 2890568