ARM: dts: msm: increase tchg-max for QRD 8x10/12 devices

Safety timers are HW timers that limit the maximum time allowed
for trickle charging and fast charging(complete charging cycle).
In case timer times out, charging will stop. For some 8x10/12
devices, we see some discharging issue especially by USB charging.
Fix this by modify this value from 150 to 250mins.

CRs-Fixed: 571072
Change-Id: I88db0808d99c26061f31431c017fb18cd83b2f7d
Signed-off-by: Zhenhua Huang <zhenhuah@codeaurora.org>