power: smb5: add support to handle pulse skip interrupt

Pulse skip IRQ is generated by PBS sequence whenever main
charger is in pulse skip mode, add support to handle pulse
skip IRQ and report pulse skip state to userspace.

Change-Id: I2c764cb17d0d8bb4abe98fa42788407ed2726628
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>