Revert "pca9468_charger: do not add 100mA offset to iin_cfg"

This reverts commit 0e26aa8c.

Reason for revert: the tighter limit doesn't help much in managing
the battery current and makes the pca9468 more likely to hit the
linear threshold where it dissipates a lot of power and heats up
the device.

Change-Id: I82c0a3e10e441a98c47cb33537e6fe568fdfde8b