pd: handle Soft Reset
pd: handle Soft Reset

When receiving a Soft Reset request, handle it as expected:
reset our ID counter, send back an Accept message.

Signed-off-by: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>

BRANCH=none
BUG=none
TEST=make buildall

Change-Id: I85d64d0349092b3a773ab6134fec0a1dcac6e284
Reviewed-on: https://chromium-review.googlesource.com/202456
Reviewed-by: Alec Berg <1a4429eeda29095a12e19a73405f80f5b7f37a63@chromium.org>
Commit-Queue: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>
Tested-by: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>

eatbyte/chromium-ec,alterapraxisptyltd/chromium-ec,mtk09422/chromiumos-platform-ec,fourier49/BIZ_EC,alterapraxisptyltd/chromium-ec,coreboot/chrome-ec,alterapraxisptyltd/chromium-ec,coreboot/chrome-ec,akappy7/ChromeOS_EC_LED_Diagnostics,md5555/ec,longsleep/ec,coreboot/chrome-ec,eatbyte/chromium-ec,longsleep/ec,eatbyte/chromium-ec,thehobn/ec,fourier49/BIZ_EC,thehobn/ec,longsleep/ec,md5555/ec,fourier49/BZ_DEV_EC,longsleep/ec,coreboot/chrome-ec,eatbyte/chromium-ec,akappy7/ChromeOS_EC_LED_Diagnostics,fourier49/BIZ_EC,alterapraxisptyltd/chromium-ec,akappy7/ChromeOS_EC_LED_Diagnostics,fourier49/BZ_DEV_EC,mtk09422/chromiumos-platform-ec,akappy7/ChromeOS_EC_LED_Diagnostics,thehobn/ec,coreboot/chrome-ec,akappy7/ChromeOS_EC_LED_Diagnostics,mtk09422/chromiumos-platform-ec,thehobn/ec,fourier49/BZ_DEV_EC,fourier49/BIZ_EC,md5555/ec,fourier49/BZ_DEV_EC,md5555/ec,mtk09422/chromiumos-platform-ec,coreboot/chrome-ec