leds: qti-flash: Fix LMH mitigation configuration

Currently, LMH mitigation is not enabled but just the option is
selected to SW. Fix it by enabling LMH mitigation properly when
the user queries for maximum flash current or LED is strobed. If
the module is enabled, LMH mitigation would get enabled in HW.

Change-Id: Ie5d7deaa6bf3ce6ed320d62972660136a0e8095d
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>