leds: qpnp-flash-v2: Enable charger mitigation

When the charger mitigation is configured based on SW,
enable it locally when the total brightness (or current
level) of all torch/flash LED devices is greater than 1 A.

CRs-Fixed: 2011199
Change-Id: I8336b3201f0780855c3dc3633179c398b9f62162
Signed-off-by: Ankit Sharma <ansharma@codeaurora.org>