ARM: dts: msm: Add Neutrino timestamp valid window property for MDM9x40

Add property to set the eAVB Timestamp Valid Window value
in Neutrino. This is set to 4 (67 ms). The Neutrino default
is 2.1 seconds for this property. 2.1 seconds causes the TX
queue to halt in the case of a bad timestamp. 67 ms is set to
prevent the TX queue from halting.

CRs-Fixed: 1056978
Change-Id: I2c452c6bbbb899fb4f3a7ac35f986ee8bd674ac3
Signed-off-by: Samuel Ahn <sahn@codeaurora.org>