ARM: dts: msm: Add pin setup for modem-QSPI mux on 8996

Auto platforms have an external mux that needs to be setup
to choose between QSPI and modem. Prior to the modem being
loaded, the mux needs to be setup for modem to use the pin.
This is a one time configuration at bootup, that is performed
by pil driver.

CRs-Fixed: 1010787
Change-Id: Ibab421fadef7e591ec84225aa4be7b55d0a54e0c
Signed-off-by: Hanumant Singh <hanumant@codeaurora.org>