usb: pd: Support revision 3.0 in sink-only mode

commit 07040df2790e ("usb: pd: policy_engine: Handle spec revision
properly") changed the spec revision handling to be 2.0 mode unless
a programmable power supply is seen. Extend this via a module
parameter to allow PD 3.0 in sink-only mode regardless of PPS when
a 3.0 source is connected.

Since the revision of the source is first encountered when
receiving the Source Capabilities message, this information is
lost by the time pd_eval_src_caps() is called. So bring back the
handling in phy_msg_received() removed in commit 07040df2790e ("usb:
pd: policy_engine: Handle spec revision properly").

Change-Id: I0485224aeadcffbfaecd0c7942c6dbcd9ddd3813
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>