OCPC: Only fetch secondary charger values when present
OCPC: Only fetch secondary charger values when present

Check the runtime charger count to verify whether secondary charger ADCs
should be pulled.

BRANCH=None
BUG=b:155963446
TEST=make -j buildall

Signed-off-by: Diana Z <cb2016afc7183e5356c690dc63b4ba817470501a@chromium.org>
Change-Id: I18d0c2717fd4db740f25c31a0766a0dfd3aef5aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2277835
Commit-Queue: Aseda Aboagye <12c9b286316a940fd31c24070da5ab64cdd4d0e7@chromium.org>
Reviewed-by: Aseda Aboagye <12c9b286316a940fd31c24070da5ab64cdd4d0e7@chromium.org>

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