pd_protocol: Allow charging @ 500mA from Rp-USB.
pd_protocol: Allow charging @ 500mA from Rp-USB.

A USB Type-C ECN "Title: Default Current Clarification for non-USB
Devices", allows a sink to draw 500mA based off of a Default USB Rp
advertisement.  This is especially important for devices which lack the
hardware to detect legacy sources via BC 1.2.  This commit will now
allow those devices to charge at 5V/500mA.

BUG=b:117805314,b:124138725
BRANCH=firmware-nocturne-10984.B,master
TEST=Flash nocturne, plug in USB-A to USB-C cable, verify cable is
detected as a charger and that we charge from it.

Change-Id: I1f40cca7246c6d671c7775869da64cf30f649dc4
Signed-off-by: Aseda Aboagye <12c9b286316a940fd31c24070da5ab64cdd4d0e7@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/1431252
Tested-by: Aseda Aboagye <12c9b286316a940fd31c24070da5ab64cdd4d0e7@chromium.org>
Commit-Queue: Aseda Aboagye <12c9b286316a940fd31c24070da5ab64cdd4d0e7@chromium.org>
Reviewed-by: Benson Leung <998395a8308946159d5d40179d81ad2bfe699e21@chromium.org>
(cherry picked from commit 9509f9aa3322fb180f51064309875589c8b90973)
Reviewed-on: https://chromium-review.googlesource.com/1565463
Commit-Ready: ChromeOS CL Exonerator Bot <fa429e5907f00867f797423aea74327bb02c91b6@appspot.gserviceaccount.com>
Tested-by: Matthew Blecker <d18f4466f2802f9c78c5c14a42b8c21fdbfabfcd@chromium.org>
Reviewed-by: Aseda Aboagye <12c9b286316a940fd31c24070da5ab64cdd4d0e7@chromium.org>
Reviewed-by: Matthew Blecker <d18f4466f2802f9c78c5c14a42b8c21fdbfabfcd@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec