ARM: dts: msm: enable hot plug support UFS cards on sdm845 platforms

We need to add the support for gpio based card insertion/removal event
detection support. But this is bit complicated as SDM845 boards have
the combo card slot which can either take SD or UFS card at one time and
there is a single GPIO assigned for card detect event. This means we need
some module which takes the responsibility of controlling (configuration,
interrupt handling) this shared card detection GPIO and pass card detection
event to both MMC and UFS card drivers so they can probe to see what card
is inserted. Kernel already have the extcon-gpio module which can be used
as gpio control module and can pass the card detection event to both MMC &
UFS card drivers. So we are adding the extcon-gpio node to UFS nodes for
all sdm845 platforms (CDP, MTP, QRD).

Change-Id: I43e36b13cc7f03480ae0e412f2a03fbddfb779f5
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>