taniks:remove charger.c
taniks:remove charger.c

taniks use bq25720 charger, and it's same as taeko.

It should use symbolic link to baseboard's charger_bq25720.c instead of
dedicated charger.c code.

I remove charger.c first then I will add charger_bq25720.c through
another CL.

BUG=b:211573264
BRANCH=brya
TEST=make buildall -j

Cq-Depend: chromium:3376683
Signed-off-by: reno.wang <62d9de2ebc2631c126311edc426119162a2ab272@lcfc.corp-partner.google.com>
Change-Id: I30c500db5a17f66da9285c2815a2c731832b981d
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3351433
Reviewed-by: Boris Mittelberg <46897f4fb5cad4b1d5146ad1fd460d7f4825bbf7@google.com>
Tested-by: Tony Tang <660c28bee34b0ba3ec183a129afce8ca0a932607@lcfc.corp-partner.google.com>
Commit-Queue: caveh jalali <08e24a66aefda7a55ca7d73f8903e0fb16eec763@chromium.org>

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