MLK-17128-1 dt-bindings: typec: add max_snk_mw property

MLK-17128-1 dt-bindings: typec: add max_snk_mw property

Add max_snk_mw property for power sink to know the max power.
Because the max mw may be smaller than the max ma multiplied by
max mv:
       max-mw <= max-mv*max-ma

After the power sink decides the PDO from source, it needs
to check the power to see if the provided power of this PDO
can match its requirement, which needs consider max_snk_mw to
know the max current it can have based on selected voltage.

Acked-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Li Jun <jun.li@nxp.com>