ARM: dts: msm: Enable dload_type selection on SM6150

Add dload_type device tree node to allow support for
selecting whether a full ramdump, minidump, or both
should be collected from a target.

Change-Id: Ie4b970f31ffdc2b1609ef32d8b973b4381edf037
Signed-off-by: Jitendra Sharma <shajit@codeaurora.org>