qcom-charger: smb-lib: support input limited state property

Add support to indicate if the switcher is acting in input limited state.
Switcher running in high duty cycle (HDC) mode should also be indicated as
input limited condition.
HDC is a 5uS pulse and sw reading the real time status register may not
indicate that it is active. Basically the presence of the pulses and the
interrupts indicate HDC and conversely their absence indicates no
HDC. Set a flag in the interrupt and clear it in a delayed work queue in
20mS. As long as the interrupts happen this flag will remain set,
indicating HDC.

Change-Id: Ia2e2d02240c36ba982f9e190b88b822b5f1b90f1
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>