wifi: ath11k: reduce the MHI timeout to 20s

wifi: ath11k: reduce the MHI timeout to 20s

Currently ath11k breaks after hibernation, the reason being that ath11k expects
that the wireless device will have power during suspend and the firmware will
continue running. But of course during hibernation the power from the device is
cut off and firmware is not running when resuming, so ath11k will fail.

(The reason why ath11k needs the firmware running is the interaction between
mac80211 and MHI stack, it's a long story and more info in the bugzilla report.)

In SUSE kernels the watchdog timeout is reduced from the default 120 to 60 seconds:

CONFIG_DPM_WATCHDOG_TIMEOUT=60

But as the ath11k MHI timeout is 90 seconds the kernel will crash before will
ath11k will recover in resume callback. To avoid the crash reduce the MHI
timeout to just 20 seconds.

Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.9

Link: https://bugzilla.kernel.org/show_bug.cgi?id=214649
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230329162038.8637-1-kvalo@kernel.org