qpnp-smb2: report main charger's share in its current_max

Currently main power supply reports the value of the input current limit
set on the usb path. This is incorrect, it should report its own
share. When parallel is disabled, it will end up reporting a value
close to current limit, rounded by 25mA steps.

Note that it should report INT_MAX when there is no limit set on
the ICL - the case for hvdcp chargers.

CRs-Fixed: 2037898
Change-Id: I9859f3d759644a08c6f762e929c471a41b1cdf8f
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>