usb_mux/amd_fp6: Handle chipset_reset
usb_mux/amd_fp6: Handle chipset_reset

The driver was only handling chipset_resume. chipset_reset also needs to
be handled. Otherwise mux won't be set on an apreset.

BUG=None
TEST=C1 display works after apreset
BRANCH=None

Signed-off-by: Rob Barnes <3ced0940a2329ce70499686f01d3d60685ec66ed@google.com>
Change-Id: I0ec336a733e51d44be7ea95f8fcfeb8a606d50a1
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2845269
Reviewed-by: Diana Z <cb2016afc7183e5356c690dc63b4ba817470501a@chromium.org>

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