iwlwifi: pcie: fix the xtal latency value for a few qu devices

We were using 5 s for some qu devices, but their xtal stabilizes
much faster than that.  Reduce the value to 500 ms.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/iwlwifi.20201008181047.d0e2253c282f.Icd2ff00adff52f6c96fb261c34fbf129ce67a00d@changeid