power: smb5: Remove FCC vote for wls pl charging

FCC_STEPPER_VOTER votes for 1.5 A upon USB removal so that FCC can ramp
up from 1.5 A, which results in faster ramp-up time. Remove that upon DC
plugin so that FCC can rise.

With 'commit 148ea9f3 ("power: smb5: Limit main charger's current
for VBATT wls pl charging")' FCC_MAIN was limited to 1 A. But now the
limiting action is performed by an override vote from userspace. The
FCC_MAIN vote is nevertheless retained for the speed of its response,
which kicks in much before userspace has the chance to cast its vote.

Change-Id: I13cd7ef467b6803633d1001fc702934a20a5e785
Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>