guybrush: Refactor FP6 mux driver to retry in S0
guybrush: Refactor FP6 mux driver to retry in S0

FP6 USB mux is not ready until sometime after S0.
Refactor driver to keep trying every 1 second until mux is ready.

BUG=b:184680878, b:184966860
TEST=C0 and C1 display connects on B1 and B2
BRANCH=None

Signed-off-by: Rob Barnes <3ced0940a2329ce70499686f01d3d60685ec66ed@google.com>
Change-Id: If744182879461d8452426deaf0e74a84dacfd510
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2819023
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