smb-lib: qpnp-smb2: fix input collapse by limiting slave FCC

The parallel charger can collapse the input adapter. Impose a
power limit on the slave charger by limiting the slave FCC.

Change-Id: I02a3dc02911646240a1ecee41584903aab971d81
Signed-off-by: Nicholas Troast <ntroast@codeaurora.org>
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>