ARM: dts: msm: add sink capabilities to PMI8998 PD PHY

Add a property to the PD PHY peripheral to specify the default
sink capabilities for USB PD as 5V @ 3A, 9V @ 3A and 12V @ 2.25A.
These are common values that should be supported on most boards,
but can be overridden as necessary.

Change-Id: I5ea95d2f0532c59f7d83cb608d939ad28a8bb28e
Signed-off-by: Jack Pham <jackp@codeaurora.org>