pd: fix power swap to sink could get wedged if missing PS_RDY
pd: fix power swap to sink could get wedged if missing PS_RDY

Fix bug if we are executing a power swap to a sink, and we don't
get PS_RDY from port partner, then we transition to SNK_DISCONNECTED
without switching our power role to sink, which could cause us to
get wedged in the wrong state if we also receive a hard reset a
little later because we will have Rd asserted but are will transition
to source role and can never get out of it.

BUG=none
BRANCH=samus
TEST=load onto two samus' and executing a bunch of power swaps. load
custom code on one samus to never send PS_RDY when switching from sink
to source and make sure when power swap occurs the state machine does
not get wedged with the wrong role.

Change-Id: I7eb2bd4d48f32770b8d7a754fee8ac8da35fa949
Signed-off-by: Alec Berg <1a4429eeda29095a12e19a73405f80f5b7f37a63@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/242760
Reviewed-by: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>

akappy7/ChromeOS_EC_LED_Diagnostics,fourier49/BZ_DEV_EC,eatbyte/chromium-ec,eatbyte/chromium-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,md5555/ec,fourier49/BZ_DEV_EC,md5555/ec,fourier49/BIZ_EC,fourier49/BIZ_EC,md5555/ec,fourier49/BZ_DEV_EC,coreboot/chrome-ec,md5555/ec,akappy7/ChromeOS_EC_LED_Diagnostics,coreboot/chrome-ec,akappy7/ChromeOS_EC_LED_Diagnostics,eatbyte/chromium-ec,fourier49/BIZ_EC,eatbyte/chromium-ec,coreboot/chrome-ec,akappy7/ChromeOS_EC_LED_Diagnostics,akappy7/ChromeOS_EC_LED_Diagnostics,fourier49/BZ_DEV_EC,fourier49/BIZ_EC