servo_v4p1: tweak USB-C timings
servo_v4p1: tweak USB-C timings

Servo_V4pX uses a passthrough charging strategy. It relays Fixed PDO via
a relay process.

However this is not based on received PS_RDY nor voltage level. Instead
it is based on fixed / pre-programmed timings (assuming fixed PMIC).

* Insufficient delay results in too-early PS_RDY (and invalid load)
* Excessive delay results in too-late PS_RDY (and hard reset)

We found some chargers are at upper end of spec tPSTransition (450ms).
These will error with current ServoV4p1 tuned timings.

* Reduce delay slightly based on rough measurements
* Refactor to fix underlying issue to be addressed later (per TODO)

BUG=b:211845598
BRANCH=servo
TEST=1. Flash ServoV4p1
     2. Monitor DUT and CHG ports with PD Analyzer
     3. Monitor CHG port with current loop
     4. Verify DUT and CHG PS_RDY relay (<tPSTransition)
     5. Verify CHG port current by CB (load valid)

Change-Id: I28696362c6eaf174db80028040f72bfaf5a15c99
Signed-off-by: Nathan K <bc2d92dd98caa1d939292891a48c5ccc55a8a8d0@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3526051
Reviewed-by: Brian Nemec <4bb9322d2721abaa797f20e8e3863e6a19240e0a@google.com>
Commit-Queue: Brian Nemec <4bb9322d2721abaa797f20e8e3863e6a19240e0a@google.com>

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