TCPM: Prevent premature reading of PD Packets in FUSB302 driver

After a successfully PD packet transmit, a PD_EVENT_RX is issued
which could trigger a premature reading of a PD Packet before
the entire packet is received.

BUG=b:71620429
BRANCH=NONE
TEST=manual
Tested on Scarlet with the following three dongles:
ASUS 3-1, (HDMI, USB, TYPEC): Tested with USB-Keyboard, TypeC power
adapter, and HP monitor.

Cable Matter 6-1, (DP, HDMI, USB, SVGA, ETHERNET, TYPEC): Tested with
USB-Keyboard, TypeC power adapter, Ethernet and HP monitor
(DP and HDMI). SVGA was not tested.

Cable Matters 6-1, (DP, DP, USB, USB, ETHERNET, TYPEC): Tested with
USB-Keyboard, USB-Mouse, Ethernet, and two HP monitors
(Scarlet was mirrored on both monitors)

Signed-off-by: Sam Hurst <shurst@chromium.org>
Change-Id: Ib07182201d954cf4b9616277f9c14bbbb337197e
Reviewed-on: https://chromium-review.googlesource.com/1015417
Commit-Ready: Sam Hurst <shurst@google.com>
Tested-by: Sam Hurst <shurst@google.com>
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
1 file changed