ARM: dts: msm: Configure SPI6 node for MSM8953

Configure SPI6 node for MSM8953 with default status
set to disabled.
Client needs to enable this instance as per usecase.
SPI6 is exposed on the sensor connector (J53) of the Open-Q board.

Change-Id: I00875b933f90d8f4e9ceed26ae8d8cff16983a05
Signed-off-by: c_vnerel <venkataraman.nerellapalli@codeaurora.org>