power: qpnp-charger: Make system awake in btc_hot_irq_debounce_work

There are two seconds sleep in qpnp_chg_btc_hot_irq_debounce_work
function to wait for charging back. System may going to suspend in this
two seconds sleep. Make system stay awake in this function.

Change-Id: Ifa8d616f7b4efe3b6013ade67114aecf13730e04
Signed-off-by: Chunmei Cai <ccai@codeaurora.org>